General Introduction to Ocean Accounts

1. Outcome

After reading this Circular, you will be able to explain what Ocean Accounts are, why they matter, and how they work -- in terms that make sense to economists, ecologists, and policymakers alike. You will understand the core framework that organises ocean-society-economy interactions, recognise how Ocean Accounts connect to established international standards like the SNA and SEEA, and identify practical starting points for implementation. This Circular is your entry point to the full Technical Guidance, which provides detailed methodologies and instructions for account compilers, data providers, and end-users across the remaining 63 Circulars.

2. Requirements

None -- this Circular introduces the Technical Guidance on Ocean Accounts for Sustainable Ocean Development as a whole. Other Circulars elaborate on the general overview provided here.

3. Guidance Material

3.1 Sustainable development of the ocean

Every country with a coastline faces the same fundamental challenge: how do you use the ocean to support livelihoods today without undermining its capacity to support livelihoods tomorrow? That challenge -- meeting present needs without compromising future generations' ability to meet theirs^[1] -- has driven decades of international frameworks from Agenda 21 and the Millennium Development Goals through to the 2030 Agenda for Sustainable Development with its 17 Goals (SDGs) and 169 associated Targets.

The ocean makes this challenge both urgent and uniquely complex. Marine and coastal environments cover 71% of Earth's surface, hold 97% of its water, and support 80% of its life forms^[2]. SDG 14 "Life Below Water" directly addresses ocean sustainability, but the ocean also underpins numerous other SDGs related to poverty alleviation, food security, climate action, and economic growth^[3]. In practice, this means decisions about fisheries management simultaneously affect food security, employment, biodiversity, and climate resilience.

From an operational standpoint, sustainable development requires maintaining or enhancing the assets that future generations will need. These include not only produced and financial capital but critically, natural capital -- which the 2025 SNA defines as the combination of natural resources (such as mineral and energy resources, biological resources, and water resources, recognised within the integrated framework of national accounts) and ecosystem assets (spatially defined areas of ecosystems, measured through SEEA Ecosystem Accounting)^[4][5][6]. The 2025 SNA formally locates natural capital within a broader multiple-capitals framework for assessing wellbeing and sustainability, alongside produced capital, human capital, and social capital (Chapters 2, 34 and 35)^[6:1].

The ocean contains and supports a wide range of these natural capital assets: individual environmental assets located in the ocean (such as aquatic resources and seabed mineral and energy resources, as defined in the SEEA Central Framework), marine and coastal ecosystem assets (as defined in SEEA Ecosystem Accounting), and produced assets supporting ocean economic activity (as defined in the SNA)^[7][8]. These assets provide services from fisheries production and coastal protection to carbon sequestration and cultural benefits. It should be noted, however, that the ocean water body itself is not treated as an environmental asset in the SEEA framework, because the stock of water is too large to be meaningful for analytical purposes (SEEA CF para 2.102)^[7:1]. This exclusion does not limit the measurement of individual assets within the ocean, such as fish stocks and seabed minerals.

In concrete terms, sustainable ocean development entails three interconnected objectives: (1) advancing ocean-based economic activities that provide sustainable livelihoods, (2) ensuring equitable distribution of benefits across society, and (3) conserving and enhancing marine ecosystems and their ecological processes^[9]. These three objectives are inseparable -- a fishery that collapses undermines both economic output and coastal community wellbeing, while a conservation policy that ignores livelihoods will lack the social support needed for long-term success.

3.2 Information requirements for sustainable development decision-making

Decisions about the ocean are only as good as the information behind them. A minister deciding whether to expand a marine protected area needs to know not just the ecological condition of the area, but also the economic activities it supports and the communities that depend on it. Traditional economic indicators like Gross Domestic Product (GDP), while valuable for measuring economic activity, cannot answer these questions -- GDP does not capture environmental depletion, equity considerations, or important values that are not traded in markets^[10]. These well-documented limitations have driven numerous "Beyond GDP" initiatives aimed at developing more comprehensive measures of societal progress^[11].

The need for better measurement is now embedded in international commitments. SDG 15.9 and the Montreal-Kunming Global Biodiversity Framework both call for the integration of ecosystem and biodiversity values into national and local planning processes, poverty alleviation strategies and accounts. SDG 17.19 calls for the development of measures of progress to complement GDP, and statistical capacity building to that end. Concerning ocean accounts specifically, Decisions 15/24 (2022) and 16/1 (2024) of the Convention on Biological Diversity States Parties call on countries to implement ocean accounts as a basis for conservation and sustainable management of marine resources and islands.

What would a decision-maker actually need to know? The information requirements for sustainable ocean development come down to three critical questions^[12]:

1. What is the current economic output from ocean-related activities? This tells you the scale and composition of the ocean economy.
2. What benefits (and disbenefits) do people and communities derive from the ocean, and how are these distributed? This tells you who gains, who loses, and whether ocean development is equitable.
3. Is ocean development sustainable over time? This tells you whether the asset base -- natural, produced, human, and social capital -- is being maintained or depleted.

Answering these questions requires multiple indicators spanning different domains. Ocean production indicators measure economic output from ocean activities. Ocean income indicators assess the benefits people receive from the ocean, including physical measures of ecosystem services and monetary measures that can be disaggregated across population segments. Changes in ocean balance sheets provide sustainability indicators by tracking changes in natural capital assets over time.

Beyond these headline indicators, decision-makers need information on specific relationships between human activities and the marine environment, including:

• Dependencies of economic sectors on marine ecosystem services
• Impacts of economic activities on marine ecosystem assets
• Distribution of benefits across different social groups
• Effectiveness of governance arrangements in managing human-ocean interactions
• Resilience of marine systems to natural and anthropogenic pressures

These information requirements demand structured approaches to data integration, processing, and presentation -- approaches that can handle complex, multi-dimensional relationships while providing clear signals to guide policy choices^[13].

3.3 Definition and scope of Ocean Accounts

Ocean Accounts give countries a common, structured way to measure the ocean, its importance to people, and what people are doing to change it. They bring together environmental, economic, and social data into a single coherent framework -- which means a fisheries scientist, a national accountant, and a coastal community planner can all work from the same evidence base.

What distinguishes Ocean Accounts from other ocean-related information compilations? Three characteristics set them apart:

1. They follow the Ocean Accounts Framework presented in this Technical Guidance. This means data from different agencies and domains are organised consistently, so you can compare across sectors, regions, and time periods without worrying about incompatible definitions or classifications.
2. They are compatible with international statistical standards, in particular the System of National Accounts (SNA) and System of Environmental-Economic Accounting (SEEA). This means Ocean Accounts speak the same language as national economic accounts, so ocean data can be directly compared with GDP figures, trade statistics, and other official statistics that governments already use.
3. They adhere to the principles of official statistics. This means the information meets the quality standards required for policy decision-making -- it is transparent, reproducible, and independently verifiable^[14].

The framework covers marine and coastal areas within national jurisdictions (territorial waters, exclusive economic zones, continental shelves) and can be applied to particular areas within these zones (e.g., bays, protected areas). It is also applicable to activities functionally connected with but spatially separate from the ocean (e.g. nutrient pollution from inland agriculture), and to areas beyond national jurisdiction though with added conceptual challenges.

Ocean Accounts are not merely collections of ocean-related statistics. Rather, they provide a coherent structure that:

• Applies accounting principles to ensure completeness and internal consistency
• Uses standardized classifications, definitions, and measurement approaches
• Enables spatial and temporal comparisons
• Facilitates the production of indicators that track progress toward policy objectives
• Supports integrated analysis of tradeoffs and synergies across different goals

While Ocean Accounts can include economic valuation of some ocean assets and services, they do not aim to determine a single "total value" of the ocean, which would be both conceptually problematic and practically impossible^[15]. Instead, they provide a framework for understanding the many ways oceans contribute to human wellbeing and for tracking changes in these contributions over time.

3.4 Functional components of Ocean Accounts

In practice, Ocean Accounts work as an information pipeline. Raw data goes in at one end; decision-relevant indicators come out the other. Understanding this pipeline helps you see where your own work fits -- whether you collect data, compile accounts, or use the results.

Figure 0.1.1 below shows the four stages of this pipeline. Reading from bottom to top: diverse data sources feed into a validation layer where statistical standards are applied, which produces standardised accounts, from which indicators and reports are derived for decision-makers.

Figure 0.1.1: Summary functional structure of Ocean Accounts

┌─────────────────────────────────────────────────────────────────────┐
│  4. INDICATORS AND REPORTS                                          │
│     For multiple decision processes                                 │
├─────────────────────────────────────────────────────────────────────┤
│  3. STANDARDISED ACCOUNTS                                           │
│     Tables, other data structures and interfaces                    │
├─────────────────────────────────────────────────────────────────────┤
│  2. DATA SHARING AND VALIDATION                                     │
│     Applying statistical principles and standards                   │
├─────────────────────────────────────────────────────────────────────┤
│  1. DATA SOURCES                                                    │
│     Social, Economic, Environmental, Customary                      │
└─────────────────────────────────────────────────────────────────────┘

The construction of Ocean Accounts begins with data collection and compilation from numerous sources: government agencies, research institutions, industry bodies, citizen science programs, and indigenous knowledge systems. These data span environmental monitoring, economic statistics, social surveys, governance information, geospatial observations, customary knowledge, and many others^[16]. A critical step is aligning these heterogeneous datasets to common spatial boundaries, classifications, and accounting periods, through data sharing and validation processes that apply the relevant international statistical principles and standards (in particular the SNA and SEEA).

Raw data are then organized into standardized accounting tables or other data structures (e.g. non-relational JSON objects) in accordance with the Ocean Accounts Framework. These structures make several conceptual distinctions, in particular between:

• Stocks of assets: with levels measured or valued at a point in time (for example fish biomass, coral reefs, or coastal infrastructure).
• Flows of goods, (dis)services or activities: physical or monetary transfers, measured or valued at a point in time, between assets and/or social or economic sectors (for example fish harvest, coastal protection from mangrove forests, pollution of the environment by economic activity).

From these tables, analysts or automated systems derive indicators and visualizations that condense complex information into decision-relevant metrics. Modern technology enables the creation of interactive dashboards that allow users to explore relationships between variables, compare scenarios, and monitor trends over time^[17]. These outputs support a wide range of decision contexts including planning, investment, regulation, monitoring and evaluation, and reporting.

3.5 Conceptual components of the Ocean Accounts Framework

The Ocean Accounts Framework starts from a simple but powerful insight: the economy does not exist alongside the environment -- it exists within it. Your fishing industry employs people in coastal communities (the economy is embedded within society), and those communities depend on healthy fish stocks (society is embedded within the environment). Damage one layer and the effects propagate inward; strengthen one and the benefits flow through the others.

This is what the Framework calls a nested superset structure. The three domains -- Economy, Society, and Environment -- are not independent pillars but concentric layers. The Framework distinguishes between flows (measurements of supply, use, activity or interaction) and stocks (measurements of asset status, extent and/or condition), each organised into three nested domain groups that mirror this structure^[18].

This nested conception aligns with the multiple-capitals framework adopted by the 2025 SNA, which identifies produced capital, human capital, social capital, and natural capital as the four pillars of sustainable wellbeing (Chapters 2, 34 and 35)^[6:2]. The three stock groups defined below map directly to this framework: SNA assets (produced capital), social assets (human and social capital), and environmental assets (natural capital). Recognising that in many countries, traditional knowledge systems do not make clear distinctions between people and nature, the Framework also supports integrated accounting for qualitative and quantitative data drawn from multiple knowledge systems.

The accounting relationships between domain groups -- the directed edges connecting specific flow groups to specific stock groups -- define the subject matter of the Technical Guidance Circulars. Figure 0.1.2 illustrates these relationships. Before looking at the diagram, here is what to notice: the three concentric layers appear twice (once for flows at the top, once for stocks at the bottom), and the labelled boxes between them describe how each type of flow connects to each type of stock. Each numbered edge represents a distinct category of accounting relationship addressed by one or more Circulars in this Technical Guidance.

Figure 0.1.2: Key conceptual components of the Ocean Accounts Framework

The accounting relationships illustrated in Figure 0.1.2 are defined in the following sections. The Framework identifies three nested domain groups for flows (FG1-FG3), three for stocks (SG1-SG3), and eleven directed edges (E1-E11) connecting them.

Domain groups for flows

The three flow groups are nested like concentric rings -- each outer group contains everything in the groups inside it, plus additional activities:

• FG1 -- Economy (SNA production boundary): These are the flows that national accountants already measure: production, income, supply and use, capital formation and financial transactions, and household distributional accounts. For ocean accounts, this encompasses all monetary flows related to ocean industries (fishing, shipping, offshore energy, tourism) as well as physical flows of natural resource inputs and residuals structured through Physical Supply and Use Tables (PSUTs) as defined in SEEA CF Chapter III^[7:2]. The 2025 SNA also provides for extended labour accounts, distributional income and consumption accounts, and measures of unpaid household service work (Chapter 16, §7.31)^[6:3][19], representing the boundary between FG1 and FG2.

• FG2 -- Society ⊃ FG1: Everything in FG1, plus activities that fall outside the SNA production boundary but are significant for sustainable ocean development. Think of subsistence fishing that feeds a family but never enters a market, volunteer beach clean-ups, community-based marine monitoring, customary marine stewardship practices, and governance activities. These activities do not show up in GDP, but they matter enormously for ocean sustainability. The 2025 SNA acknowledges the importance of measuring these extended activities for wellbeing assessment (Chapters 16, 34)^[6:4][19:1].

• FG3 -- Environment ⊃ FG2: Everything in FG2, plus ecological processes and interactions within the environment that maintain ecosystem functioning but are not directly used by people. These include intermediate ecosystem services (nutrient cycling, seed dispersal between ecosystems), biogeochemical cycles (carbon, nitrogen, phosphorus), energy flows through food webs, species migrations, and larval dispersal -- dynamic processes that connect different marine ecosystems and sustain the capacity of ecosystems to supply final services^[8:1]. An ecologist would recognise these as the ecological infrastructure that keeps the whole system running.

Domain groups for stocks

The stock domain groups follow the same nested structure. They map directly to the 2025 SNA's multiple-capitals framework for measuring sustainability (Chapters 34-35)^[6:5], which means ocean accounts can be directly compared with national-level sustainability assessments:

• SG1 -- SNA assets (produced capital): The balance sheets, physical asset inventories, and financial positions recorded within the SNA framework. For ocean accounts, this includes produced assets such as vessels, port infrastructure, aquaculture facilities, and offshore platforms; and financial assets such as fishing licences (where treated as assets) and ocean-related investments. These correspond to "produced capital" in the SNA 2025 multiple-capitals framework.

• SG2 -- Social assets ⊃ SG1: Everything in SG1, plus the social structures and conditions that enable human activities. These include community conditions (health, education, food security in coastal populations), governance arrangements (legal frameworks, customary tenure, marine protected area designations), and institutional capacities. These correspond to "human capital" and "social capital" in the SNA 2025 framework. In practice, this means ocean accounts can track whether the human and institutional foundations of ocean management are strengthening or weakening over time. Measurement approaches draw on the SEEA EA treatment of cultural services (Chapter 6) and the governance indicators described in TG-3.7 Governance Accounts^[8:2].

• SG3 -- Environmental assets ⊃ SG2: Everything in SG2, plus natural capital. This includes individual environmental assets as defined in the SEEA Central Framework (fish stocks, seabed minerals, water resources) and ecosystem assets as defined in SEEA Ecosystem Accounting (coral reefs, mangroves, seagrass meadows, pelagic ecosystems), measured through extent and condition accounts^{[7:3][8:3][20]}. These correspond to "natural capital" in the SNA 2025 framework. When a country's environmental asset accounts show declining condition, that is an early warning that the ecological foundations of ocean productivity are being eroded.

Individual environmental assets in the ocean domain can be classified according to the 2025 SNA's five categories of natural resources^[5:1][6:6]: (1) land, including coastal land and the seabed; (2) mineral and energy resources, including seabed minerals, offshore hydrocarbons, and renewable energy resources such as offshore wind and tidal energy (AN322); (3) biological resources, including aquatic resources such as fish stocks; (4) water resources; and (5) other natural resources.

Ecosystem condition is measured using the SEEA EA Ecosystem Condition Typology (ECT), which organises condition variables into three groups and six classes: abiotic characteristics (physical state and chemical state), biotic characteristics (compositional state, structural state, and functional state), and landscape/seascape characteristics^[8:4][21]. Condition is measured relative to a reference condition reflecting the natural or undegraded state of the ecosystem (SEEA EA para 5.69)^[8:5].

An important distinction applies to aquatic biological resources. Aquaculture production (cultivated biological resources) falls within the SNA production boundary: the growth of organisms in aquaculture facilities is treated as a process of production, and these resources are classified as produced assets. In contrast, wild-capture fisheries target natural biological resources that are outside the production boundary until harvest, and are subject to depletion accounting. This distinction, elaborated in SEEA CF Section 5.9^[7:4], has fundamental implications for how these resources are recorded in ocean accounts -- including whether changes in stock are treated as changes in produced capital or as depletion of natural resources. For a fisheries manager, this means aquaculture expansion shows up as investment while overfishing shows up as asset depletion -- two very different signals for sustainability.

Accounting relationships between domain groups

The eleven directed edges in Figure 0.1.2 define the accounting relationships between flow groups and stock groups. Each edge represents a distinct category of interaction that is the subject of one or more Technical Guidance Circulars. Together, these edges provide a comprehensive map of the relationships that ocean accounts are designed to measure. The table below serves as a roadmap: find the relationship you care about, and the "Primary Circular(s)" column tells you where to go for detailed guidance.

The distinction between E1 and E2 (economic vs. social residuals to the environment) and between E9 and E10 (ecosystem services to the economy vs. to society) reflects a reality that matters for policy: human-environment interactions extend well beyond market transactions. E2 captures residuals from activities outside the SNA production boundary (e.g., household plastic waste, subsistence fishing bycatch), while E10 captures ecosystem contributions to wellbeing that are not mediated through market transactions (e.g., cultural values of coral reefs, spiritual significance of marine environments). If you only measured the market-based edges, you would miss much of what coastal communities actually depend on. The social edges E4-E8 represent the least standardised but increasingly recognised relationships between social capital and both economic and environmental outcomes, drawing on the 2025 SNA's expanded treatment of wellbeing and sustainability measurement^[6:7].

Spatial data framework

Ocean systems are inherently spatial -- a pollution source upriver, a fishery offshore, and a coastal community in between are all connected through geography. The Framework employs a spatially explicit approach with Basic Spatial Units (BSUs) as the foundation. These units may be differentiated into terrestrial, coastal, and marine BSUs, establishing connections between terrestrial activities that impact the ocean, coastal transition zones, and marine environments. Depth layers within BSUs enable a three-dimensional perspective that accommodates the complex spatial nature of ocean systems.

3.6 Relationship to other standards and approaches

Ocean Accounts do not start from scratch. They build on established international standards and connect to a range of related approaches. Understanding these relationships helps you see what Ocean Accounts inherit for free (tested methodology, institutional infrastructure) and what they add (ocean-specific spatial detail, social domain integration, cross-domain coherence).

System of National Accounts (SNA)

The System of National Accounts (SNA)^[5:2] provides the foundational structure for measuring economic activity. Countries already compile national accounts using the SNA, so building ocean accounts on this foundation means the results can be directly compared with existing economic statistics. The 2025 SNA, adopted by the United Nations Statistical Commission in March 2025, represents a significant advance over the 2008 SNA^[22] in its treatment of environmental and sustainability dimensions. Notably, the 2025 SNA now treats the depletion of natural resources as a cost of production alongside depreciation -- which means that a country depleting its fish stocks will see this reflected in its net income measures, giving a more honest picture of economic performance. The 2025 SNA gives more emphasis to net income measures such as Net Domestic Product (NDP) as the conceptually preferred measure of economic growth (Annex 4, para A4.59). It also formally defines natural capital, introduces new chapters on wellbeing and sustainability measurement (Chapters 34-35), and explicitly identifies ocean accounting as an application of its thematic accounting framework (para 35.63)^[6:8].

System of Environmental-Economic Accounting (SEEA)

The System of Environmental-Economic Accounting (SEEA) includes two complementary standards: the SEEA Central Framework (SEEA-CF)^[7:5] and SEEA Ecosystem Accounting (SEEA-EA)^[8:6]. SEEA-CF provides methodology for measuring individual environmental assets (e.g., fish stocks, minerals) and their flows into the economy, structured through Physical Supply and Use Tables and asset accounts. SEEA-EA focuses on ecosystem accounting, including ecosystem extent, condition, and services. Ocean Accounts adapt these approaches specifically for the marine domain, addressing challenges such as three-dimensional ecosystem delineation and fluid boundaries^[23]. In practice, this means a country that has already implemented SEEA for terrestrial ecosystems can extend the same methodological approach to its marine and coastal areas.

Ocean Economy Satellite Accounts

Ocean Economy Satellite Accounts are specialized economic accounts that disaggregate and measure ocean-related economic activities. These complement traditional national accounts by providing greater detail on maritime sectors that are often hidden within broader classifications^[24]. For example, fishing revenue might be aggregated with agriculture in standard accounts -- an ocean economy satellite account separates it out, making the ocean's economic contribution visible to policymakers.

Natural Capital Accounting (NCA)

Natural Capital Accounting (NCA) broadly refers to approaches that measure natural assets and their contributions to the economy. Ocean Accounts represent a specific application of NCA principles to the marine domain, with particular attention to spatial detail and ocean-specific challenges^[25].

Corporate disclosure frameworks

Corporate disclosure frameworks like the Task Force on Climate-related Financial Disclosures (TCFD) and emerging frameworks for nature-related financial disclosures focus on enterprise-level reporting. While Ocean Accounts primarily support public policy at national and subnational scales, the concepts and data can inform corporate reporting on ocean dependencies and impacts^[26]. A shipping company reporting on its nature-related risks, for example, could draw on ocean account data to understand the ecosystem services its operations depend on.

Marine Spatial Planning (MSP)

Marine Spatial Planning (MSP) frameworks organize the spatial allocation of ocean activities. Ocean Accounts can provide standardized data inputs to MSP processes and help evaluate outcomes of spatial planning decisions over time^[27]. Because both MSP and ocean accounts use spatial units, the two approaches are natural complements -- MSP defines where activities can happen, and ocean accounts measure what actually happens and what changes as a result.

3.7 Data quality and uncertainty

All data have limitations, and ocean data are no exception. Acknowledging uncertainty is not a weakness -- it is a mark of rigorous accounting. Decision-makers are better served by an honest account with documented limitations than by a confident number that hides its assumptions.

The SEEA EA identifies six dimensions of data quality relevant to environmental-economic accounting: relevance, timeliness, accuracy, coherence, interpretability, and accessibility, together with the quality of the institutional environment in which the data are compiled (SEEA EA para 2.86)^[8:7].

In addition, four categories of uncertainty are particularly pertinent to ecosystem accounting and apply directly to ocean accounts:

1. Uncertainty related to physical measurement of ecosystem services and ecosystem assets
2. Uncertainty in the valuation of ecosystem services and ecosystem assets
3. Uncertainty related to the dynamics of ecosystems and changes in flows
4. Uncertainty regarding future prices and values (SEEA EA para 2.90)^[8:8]

It is important that all accounting work document the scope of measurement, the definitions applied, the methods used, and the assumptions made (SEEA EA para 2.95). Circular 0.7 addresses quality assurance and quality control procedures for ocean accounts in detail.

3.8 Implementation approaches and starting points

You do not need to build a complete set of ocean accounts before they become useful. Countries typically adopt modular approaches, building accounts progressively rather than attempting comprehensive implementation from the outset. The key is to start with the questions your country needs to answer, then build the accounts that address those questions.

Common entry points include:

• Thematic focus: Start with a pressing policy question. Marine protected area management, sustainable fisheries, coastal tourism development, marine pollution reduction, climate change adaptation, and blue economy development strategies each provide a clear motivation and a defined scope for initial accounts^[28].

• Geographic scope: Start with the area that matters most. This could be the national level (whole exclusive economic zone), subnational regions, specific ecosystems (coral reefs, mangroves), marine protected areas, or areas of high economic significance or environmental vulnerability.

• Existing data availability: Start with what you already have. National statistical compilations, environmental monitoring programs, economic surveys, marine spatial data infrastructures, research programs, and administrative datasets all provide raw material for initial accounts^[29].

• Institutional arrangements: Start with the institutions ready to collaborate. National statistics office-led, environment agency-led, multi-agency collaborative efforts, and research institution partnerships each offer different strengths.

The modular, adaptive nature of Ocean Accounts allows for a "learn-by-doing" approach. Initial pilot studies often focus on feasibility assessment and capability development before scaling to more comprehensive implementation. Countries with limited resources may begin with rapid assessments using global datasets before developing more detailed national accounts^[30].

4. Acknowledgements

This Circular has been approved for public circulation and comment by the GOAP Technical Experts Group in accordance with the Circular Publication Procedure.

Authors: [To be confirmed]

Reviewers: [To be confirmed]

5. References