APA način citiranja (7. izdanje)

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

Čikaški stil citiranja (17. izdanje)

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

MLA način citiranja (9. izdanje)

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