Department of Homeland Security – Voice Over IP

Federal Communications Commission – Voice Over Internet Protocol (VoIP) – Federal Communications Commission

TMC Net – VoIP Security Monitoring and Management; What Every Security Professional Needs to Know

NIST SP 800-53: SC-19 Voice Over Internet Protocol

NIST SP 800-53: SC-2 Application Partitioning

Gartner – Email Security Platforms Reviews and Ratings

CSO – What are DMARC, SPF and DKIM? How to master email security with these protocols

DoD Procurement Tool Box – FAQ 98: Protect the confidentiality of CUI at Rest

NIST SP 800-53: SC-28 Protection of Information at Rest

NIST SP 800-53: SC-10 Network Disconnect