Papers

Buffer Overflows Demystified [English] [Turkish]
One of the most cited papers about Buffer Overflows, along with aleph1′s (Elias Levy) famous Smashing the stack for fun and profit. The env method has been discussed for the first time in this article. Considered the best clarifying paper in its area. Some of the citations include:

Wikipedia
Beyond stack smashing: recent advances in exploiting buffer overruns.
By Microsoft Research. Published in IEEE Security Volume 2 Issue 4, July 2004
An analysis of buffer overflows.
By SANS Institute. Link here.
How a program works.
By Governmentsecurity.org Link here.
Metasploit Framework.
By Symantec.
More…

Designing Shellcode Demystified [English]
One of the most cited papers about Shellcodes and Buffer Overflows.
IP Spoofing with the BSD Raw Sockets Interface [English] [Turkish]
Hooking Filters for Fun and Profit [English]
More papers @enderunix.org

Books

Kurulum Yönetim ve Ağ Servisleri ile FreeBSD İşletim Sistemi. 2004, Açık Akademi Yayınları

VoIPong.
Voice over IP call detector. One of the most advanced VoIP sniffer. Included in Backtrack and FreeBSD. Has been awarded the IBM Turk Linux Award, 2004.
Video – 15 Aralık 2004, NTV Haber.
Isoqlog. Regarded as the best open source qmail log analyzer. Has been awarded the IBM Turk Linux Award, 2002.
Spamguard. Spam blocker for many mail servers including qmail, sendmail, postfix and exim.
Aget. Multi-threaded download manager for unix based operating systems including Mac OS X, FreeBSD, Linux and other unices.
Hafiye. My graduation thesis. A POSIX compliant customizable TCP/IP network analyzer and sniffer.