http://gmplib.org
http://dlmf.nist.gov/
http://gnuplot.sourceforge.net/demo/
http://www.kurims.kyoto-u.ac.jp/~ooura/fft.html
http://www.cosc.canterbury.ac.nz/research/RG/alg/dict.html
Hash functions: http://www.burtleburtle.net/bob/hash/doobs.html