APA (7th ed.) Citation

Barker, K. (2012). CCNA security 640-554: Official cert guide (1. pr.).

Chicago Style (17th ed.) Citation

Barker, Keith. CCNA Security 640-554: Official Cert Guide. 1. pr. 2012.

MLA (9th ed.) Citation

Barker, Keith. CCNA Security 640-554: Official Cert Guide. 1. pr. 2012.

Warning: These citations may not always be 100% accurate.