Integrated Services Digital Network (ISDN) - Explicit Call Transfer (ECT) supplementary service - Digital Subscriber Signalling System No. one (DSS1) protocol - Part 1: Protocol specification
Integrated Services Digital Network (ISDN) - Signalling System No.7 (SS7) - ISDN User Part (ISUP) version 4 for the international interface - Part 14: Explicit Call Transfer (ECT) supplementary service [ITU-T Recommendation Q.732, clause 7 (1996) and implementors guide (1998), modified]
