APA (7th ed.) Citation

Ziegler, R. L. (2000). Linux firewalls. New Riders.

Chicago Style (17th ed.) Citation

Ziegler, Robert L. Linux Firewalls. Indianapolis, Ind.: New Riders, 2000.

MLA (9th ed.) Citation

Ziegler, Robert L. Linux Firewalls. New Riders, 2000.