Absolute FreeBSD : the complete guide to FreeBSD
Lucas, Michael W. (Michael Warren), 1967-
San Francisco : No Starch Press, ©2008.

Absolute FreeBSD : the complete guide to FreeBSD
Lucas, Michael W. (Michael Warren), 1967- author.
San Francisco : No Starch Press, [2019]

The Book of PF, 3rd Edition
Hansteen, Peter, author.
No Starch Press, 2014.

BSD UNIX toolbox : 1000+ commands for FreeBSD, OpenBSD, and NetBSD power users
Negus, Chris, 1957-
Indianapolis, IN : Wiley Pub., ©2008.

The Design and Implementation of the 4.4BSD Operating System
Consultant, Marshall, author.
Addison-Wesley Professional, 1996.

Designing BSD rootkits : an introduction to kernel hacking
Kong, Joseph.
San Francisco : No Starch Press, 2007.

Der eigene Server mit FreeBSD 9 : Konfiguration, Sicherheit und Pflege
Niessen, Benedikt.
Heidelberg : Dpunkt Verlag, 2012.

The FreeBSD 6.2 crash course
Matzan, Jem.
Sebastopol, Calif. : O'Reilly, 2007.

FreeBSD 6 unleashed
Tiemann, Brian.
Indianapolis, Ind. : Sams, 2006.

FreeBSD device drivers : a guide for the intrepid
Kong, Joseph.
San Francisco : No Starch Press, ©2012.

FreeBSD unleashed
Tiemann, Brian.
[Indianapolis] : Sams, ©2002.

Mastering FreeBSD and OpenBSD security
Korff, Yanek.
Sebastopol, CA : O'Reilly, ©2005.

Sams teach yourself FreeBSD in 24 hours
Urban, Michael C.
Indianapolis, IN : Sams Pub., ©2003.