1. Lecture Notes in Computer Science;W. Aalst,2003
2. Lecture Notes in Computer Science;L. Bocchi,2003
3. Thatte, S.: XLANG: Web Service for Business Process Design,
http://www.gotdotnt.com/team/xmlwsspecs/xlang-c/default.html
4. Leymann, F.: WSFL: Web Serices Flow Languag,
http://www-3.ibm.com/software/solutions/webservices/pdf/WSDL.pdf
5. BPEL4WS, Business Process Execution Language for Web Service (2003),
http://www.siebel.com/bpel