Robar, A. (2009). FreePBX 2.5 powerful telephony solutions: Configure, deploy, and maintain an enterprise-class VoIP PBX. Packt Publishing.
Dyfyniad Arddull ChicagoRobar, Alex. FreePBX 2.5 Powerful Telephony Solutions: Configure, Deploy, and Maintain an Enterprise-class VoIP PBX. Birmingham, UK: Packt Publishing, 2009.
Dyfyniad MLARobar, Alex. FreePBX 2.5 Powerful Telephony Solutions: Configure, Deploy, and Maintain an Enterprise-class VoIP PBX. Packt Publishing, 2009.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.