4Li Hongxin,Xue Jinsong,Zhu Yulnlong.Multi-level description approach to flexible workflow model, International Conefrence on Advanced Manuafcutring System and Manuafcutring Automation[C], 2000, Guangzhou: China.
8OMG. Workflow Management Facility Specification, Version 1.2, 2000.4. http://www.omg.org
9WfMC. Workflow Management Coalition Interface1: Process Definition Interchange Process Model. WFMC-TC-1016-P, Version 1.1, 1999.10. htttp://www.wfmc.org
10Sadiq W, Orlowska M. Analyzing process models using graph reduction techniques. Information Systems, 2000,25(2): 117~134