http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/elicense.html Commercial Use of Mersenne Twister 2001/4/6 Until 2001/4/6, MT had been distributed under GNU Public License, but after 2001/4/6, we decided to let MT be used for any purpose, including commercial use. 2002-versions mt19937ar.c, mt19937ar-cok.c are considered to be usable freely.