1. The HCSP Constraint Solver web page. http://tx.technion.ac.il/mveksler/HCSP/
2. Fourth international CSP solver competition (2009). http://cpai.ucc.ie/09/index.html
3. Minizinc challenge (2014). http://www.minizinc.org/challenge2014/
4. Opturion CPX - tool description (2014). http://www.minizinc.org/challenge2014/description_opturion_cpx.txt
5. Beckert, B., Hähnle, R., Manyá, F.: The SAT problem of signed CNF formulas, pp. 59–80 (2000)