1. ITU-T Recommendation Q.1201 Principles of Intelligent Network Architecture
2. ITU-T Recommendation Q.1214 IN Distributed Functional Architecture for IN CS-1
3. ITU-T Draft Recommendation F.851 UPT Service Description
4. Draft ETSI Technical Report NA-71303 UPT Phase 1: Architecture and functionalities for interworking
5. Draft ETSI Technical Report NA-71205 UPT Phase 1 subscriptions, service profile and information model