www.kernel.org/—Linux Kernel Archives. The source of all development discussion for the Linux kernel.
www.kerneltraffic.org/kernel-traffic/index.html—Linux Kernel Traffic. Summarized version and commentary of the Linux Kernel mailing list produced weekly.
www.gnu.org/—Free Software Foundation. Source of manuals and software for programs used throughout the kernel compilation process. Tools such as
gcc have their official documentation ...