APA (7th ed.) Citation

Cisco Systems, Inc, Schulz, D. A., & Hannah, A. C. (2011). CCNP voice CIPT2 642-457 quick reference (2nd ed.). Cisco Press.

Chicago Style (17th ed.) Citation

Cisco Systems, Inc, David Author Schulz, and Alex Contributor Hannah. CCNP Voice CIPT2 642-457 Quick Reference. 2nd ed. [Place of publication not identified]: Cisco Press, 2011.

MLA (9th ed.) Citation

Cisco Systems, Inc, et al. CCNP Voice CIPT2 642-457 Quick Reference. 2nd ed. Cisco Press, 2011.