APA (7th ed.) Citation
Hansteen, P. N. M. (2015). The book of PF: A no-nonsense guide to the OpenBSD firewall (Third edition.). No Starch Press.
Chicago Style (17th ed.) Citation
Hansteen, Peter N. M. The Book of PF: A No-nonsense Guide to the OpenBSD Firewall. Third edition. San Francisco, [California]: No Starch Press, 2015.
MLA (9th ed.) Citation
Hansteen, Peter N. M. The Book of PF: A No-nonsense Guide to the OpenBSD Firewall. Third edition. No Starch Press, 2015.
Warning: These citations may not always be 100% accurate.