1. Ahn, G., Sandhu, R., Kang, M., Park, J.: Injecting RBAC to secure a web-based workflow system. In: Proc. of RBAC 2000. ACM Press, New York (2000)
2. BPEL. Business process execution language for web services version 1.1,
http://www-128.ibm.com/developerworks/library/ws-bpel/
3. BPEL 2.0 Working Draft. Web services business process execution language version 2.0 (2004),
http://www.oasis-open.org/apps/org/workgroup/wsbpel/
4. Fu, X., Bultan, T., Su, J.: Analysis of interacting BPEL web services. In: Proc. of WWW 2004. ACM Press, New York (2004)
5. Lecture Notes in Computer Science;S. Hinz,2005