1.9.3 Books
Practical UNIX & Internet Security, 2nd Ed., Simon Garfinkel and Gene Spafford (O'Reilly & Associates, 1996, ISBN 1-56592-148-8).
Firewalls and Internet Security, W. R. Cheswick and S. M. Bellovin (Addison-Wesley, 1994).
Building Internet Firewalls, D. Brent Chapman and Elizabeth D. Zwicky (O'Reilly & Associates, Inc. 1995 ISBN 1-56592-124-0).
Improving the Security of Your UNIX System, David A. Curry (SRI International), available via anonymous ftp from www-wks.acs.ohio-state.edu:/pub/security/security-doc.tar.