System Architecture For 5G System (TS 23.501):
https://www.etsi.org/deliver/etsi_ts/123500_123599/123501/15.02.00_60/ts_123501v150200p.pdf
Procedures for 5G System (TS 23.502):
https://www.etsi.org/deliver/etsi_ts/123500_123599/123502/15.02.00_60/ts_123502v150200p.pdf
Policy and Charging Control Framework (TS 23.503):
https://www.etsi.org/deliver/etsi_ts/123500_123599/123503/15.02.00_60/ts_123503v150200p.pdf
Service Based Architecture (TS 29.500):
https://www.etsi.org/deliver/etsi_ts/129500_129599/129500/15.00.00_60/ts_129500v150000p.pdf
Security Architecture & Procedures for 5G system (TS 33.501):
https://www.etsi.org/deliver/etsi_ts/133500_133599/133501/15.01.00_60/ts_133501v150100p.pdf
VoNR, Handovers, Registration, SMS, Location Services (TS 23.502):
https://www.etsi.org/deliver/etsi_ts/123500_123599/123502/15.02.00_60/ts_123502v150200p.pdf