1. SPIN homepage, http://www.spinroot.com/
2. ASAP download, http://www.daimi.au.dk/~ascoveco/download.html
3. The ASCoVeCo Project: Advanced State Space Methods and Computer tools for Verification of Communication Protocols, http://www.daimi.au.dk/~ascoveco/
4. Lecture Notes in Computer Science;T. Bao,2005
5. CPN Tools homepage, http://www.daimi.au.dk/CPNTools/