7OASIS Web Services Business Process Execution Language (WSBPEL) TC, Business Process Execution Language for Web Services [ OL ]. http://docs, oasis-open, org/wsbpel/2. 0/wsbpel - v2. 0. pdf, 2008.
8Bing Liu, Huaping Chen. Web service composition and analysis: a petri-net based approach, semantics[ A ]. Proceedings of the 1^st International Conference on Semantics, Knowledge and Grid[C]. Beijing: IEEE Computer Society,2005:111 - 121.
9P Wohed, W M P van der Aalst, M Dumas, and A H M ter Hofstede. Analysis of web services composition languages: the case of WS-BPEL [ A ]. Proceeding of the 22^nd International Conference on Conceptual Modeling [ C]. Berlin: Springer-Verlag, 2003: 200 - 215.
10Yuliang Shi, Liang Zhang, Bing Liu, Fangfang Liu, Lili Lin, Baile Shi. A formal specification for web services composition and verification[ A ]. Proceedings of the 5th Interntional Conference on Computer and Information Technology[C]. Shanghai: IEEE Computer Society,2005:252- 256.
