Research on Linux Kernel Development
* Study: Linux Kernel Development: How Fast it is Going, Who is Doing It, What They are Doing, and Who is Sponsoring It. Linux Foundation, 2015
Summary
"Since 2005, some 11,800 individual developers from nearly 1,200 different companies have contributed to the kernel. The Linux kernel, thus, has become a common resource developed on a massive scale by companies which are fierce competitors in other areas.
This is the sixth in a series of regular updates to this document, which has been published roughly annually since 2008. It covers development through the 3.18 release (which came out on December 7, 2014), with an emphasis on the releases 3.11 to 3.18. It was a typically busy period, with eight kernel releases created, many significant changes made, and continual growth of the kernel developer and user communities."