Configure NTP Authentication with Cisco IOS Devices
NTP Peer Explanation and Configuration - Study CCNP
NTP Configuration on Cisco Devices - ICTShore.com
Configure and Verify NTP Operating in Client and Server Mode - GeeksforGeeks
Configure Cisco Switch For NTP - YouTube
Learn how to configure NTP Server and NTP Client on cisco Router – Learn Linux CCNA CCNP CEH CISSP CISA Penetration-Testing Bug Bounty IPv6 Cyber-Security Network-Security Online
Use Best Practices for Network Time Protocol - Cisco
Changing the NTP source in CUCM from CLI and other helpful information: - Cisco Community