# Evidence sources

## R01 — GnuCash Accounting Concepts

- Organization: GnuCash project.
- Source/version: official v5 software guide, sections 2.1.3–2.1.4.
- URL: [Accounting Concepts](https://www.gnucash.org/docs/v5/C/gnucash-guide/basics-accounting1.html).
- Accessed: 2026-10-24.
- Jurisdiction: general accounting mechanics.
- Supports: normal debit/credit directions and equality.
- Limitations: no banking compliance/recognition authority.

## R02 — Federal Reserve H.8

- Organization: Federal Reserve Board.
- Source/version: statistical release, observed release date 2026-10-23.
- URL: [Commercial bank balance sheets](https://www.federalreserve.gov/releases/h8/current/default.htm).
- Accessed: 2026-10-24.
- Jurisdiction: United States; classification context only.
- Supports: deposits displayed as bank liabilities.
- Limitations: current URL changes; no statistics/customer event reused.

## R03 — SIX currency list

- Organization: SIX, ISO 4217 Maintenance Agency.
- Source/version: official List One XML Pblshd 2026-09-17; USD 840 / EUR 978 selected rows.
- URL: [XML](https://www.six-group.com/dam/download/financial-information/data-center/iso-currrency/lists/list-one.xml); [maintenance context](https://www.six-group.com/en/products-services/financial-information/market-reference-data/data-standards.html).
- Accessed: 2026-10-24.
- Jurisdiction: international currency reference.
- Supports: pinned USD/EUR exponent 2.
- Limitations: no claim all currencies have two decimals; review whitelist explicitly.

## R04 — PostgreSQL Transactions

- Organization: PostgreSQL Global Development Group.
- Source/version: PostgreSQL 18 official documentation, section 3.4.
- URL: [Transactions](https://www.postgresql.org/docs/18/tutorial-transactions.html).
- Accessed: 2026-10-24.
- Jurisdiction: technical database semantics.
- Supports: all-or-nothing grouping and visibility.
- Limitations: pure snapshot functions do not test database durability/concurrency.

## R05 — RFC 3339

- Organization: IETF/RFC Editor.
- Source/version: standards-track RFC, July 2002; current page notes update RFC 9557.
- URL: [RFC 3339](https://www.rfc-editor.org/rfc/rfc3339).
- Accessed: 2026-10-24.
- Jurisdiction: Internet representation.
- Supports: timestamp/offset concepts.
- Limitations: UTC milliseconds/no leap seconds are selected subset, not whole RFC.

## R06 — Safe integer maximum

- Organization: Ecma TC39.
- Source/version: official living specification accessed on date.
- URL: [Number.MAX_SAFE_INTEGER](https://tc39.es/ecma262/multipage/numbers-and-dates.html#sec-number.max_safe_integer).
- Accessed: 2026-10-24.
- Jurisdiction: language semantics.
- Supports: Number safe integer maximum 9007199254740991.
- Limitations: money strings/30 digit limits are implementation choices.

Historical decision: **not useful** for deterministic mechanics. All institution/customer/account/event/amount data is fictional and synthetic. Expected arithmetic is author-derived. No confidential or provider data appears.