1. CHOCO web page,
http://www.emn.fr/z-info/choco-solver/
2. CVC3 web page,
http://www.cs.nyu.edu/acsys/cvc3/
3. Opt4J web page,
http://opt4j.sourceforge.net/
4. TSAFE maryland,
http://www.cs.umd.edu/~mvz/cmsc435-s09/
5. TSAFE mit,
http://sdg.csail.mit.edu/TSAFE/downloads/