@inproceedings{YYLWorkflow07,
  author    = {Ping Yang and Zijiang Yang and Shiyong Lu},
  title     = {Formal Modelling and Analysis of Scientific Workflows Using 
Hierarchical State Machines},
  booktitle = {International Workshop on Scientific Workflows and Business 
Workflow Standards in e-Science}, 
  publisher = {IEEE Computer Society Press},
  note = {to appear},
  year      = {2007}
}