The REA ontology has been accepted in August 2007 as the international ISO/IEC standard 15944-4, referred to as the Open-edi Business Transaction Ontology (OeBTO). Different reference models and methodologies for designing business services in e-collaboration contexts (e.g., the UN/CEFACT’s Modeling Methodology (UMM), the E-Commerce Integration Meta-Framework (ECIMF), the ISO/IEC 14662:1997 reference model for electronic data interchange) use REA as underlying business ontology for grounding the constructs of their modeling formalisms.