HL7 Version 3 Standard: Refinement, Constraint and Localization to Version 3 Messages, Release 2
This HL7 Version 3 (V3) standard describes the processes whereby HL7 V3 artifact specifications may be refined, constrained and extended to support implementation designs, conformance profiles, and realm-specific standards.
ANSI/HL7 V3 RCL, R2-2007 (R2020)
https://www.hl7.org/implement/standards/product_brief.cfm?product_id=76