Cita APA (7a ed.)

Cisco Systems, Inc, & Hooper, H. A. (2012). CCNP security VPN: 642-647 official cert guide (1st edition.). Cisco Press.

Cita Chicago Style (17a ed.)

Cisco Systems, Inc, y Howard Author Hooper. CCNP Security VPN: 642-647 Official Cert Guide. 1st edition. [Place of publication not identified]: Cisco Press, 2012.

Cita MLA (9a ed.)

Cisco Systems, Inc, y Howard Author Hooper. CCNP Security VPN: 642-647 Official Cert Guide. 1st edition. Cisco Press, 2012.