Using Asterisk as a Conference Bridge for Your Cisco CallManager | Greg Sowell Saves The World
VoIP Audio/Video Conferencing — AREDN Documentation Latest Nightly Build documentation
Trixbox v2.6.1.1 with VarPhonex Trunk Installation Guide
Tutorial - Jitsi / Jigasi & FreePBX integration. Along with Asterisk IVR to use Jitsi conference mapper API - Install & Config - Jitsi Community Forum - developers & users