APA引文

Robar, A. (2009). FreePBX 2.5 powerful telephony solutions: Configure, deploy, and maintain an enterprise-class VoIP PBX. Packt Publishing.

芝加哥风格引文

Robar, Alex. FreePBX 2.5 Powerful Telephony Solutions: Configure, Deploy, and Maintain an Enterprise-class VoIP PBX. Birmingham, UK: Packt Publishing, 2009.

MLA引文

Robar, Alex. FreePBX 2.5 Powerful Telephony Solutions: Configure, Deploy, and Maintain an Enterprise-class VoIP PBX. Packt Publishing, 2009.

警告：这些引文格式不一定是100％准确.