TCP-Fit was implemented by following the pseudocode and some of the recommendations of this paper: http://www.tcpengines.com/wp-content/uploads/2013/11/tcp-whitepaper.pdf
TCP-Illinois is a port from the Linux kernel implementation at: http://lxr.free-electrons.com/source/net/ipv4/tcp_illinois.c
Both mechanisms reached the final stage, yet use them with caution.
Have fun and keep coding!