Terrestrial Trunked Radio (TETRA) - Voice plus Data (V+D) - Part 12: Supplementary services stage 3 - Sub-part 13: Call Completion to Busy Subscriber (CCBS)
Terrestrial Trunked Radio (TETRA) - Voice plus Data (V+D) - Part 3: Interworking at the Inter-System Interface (ISI) - Sub-part 5: Additional Network Feature for Mobility Management (ANF-ISIMM)
