Resources on the site
Interactive map of GNU/Linux OS and FOSS and poster
"GNU/Linux is my home" - map of GNU/Linux system
Interactive map of Linux kernel
Linux inside
Linux kernel poster
Linux Technology Reference (single page view)
Linux Device Drivers, 3rd Edition
Advanced Linux Programming
Managing Projects with GNU make
Introduction to Linux
Bash Guide for Beginners
Advanced Bash-Scripting Guide
GNU/Linux Command-Line Tools Summary
Linux Filesystem Hierarchy
The Linux Kernel Module Programming Guide
The Linux System Administrator's Guide
Linux Network Administrators Guide
Autobook: GNU Autoconf, Automake, and Libtool src

Other:
Business proposal to production of ointment for treatment skin diseases