@inproceedings{Simpson_et_al_2005b,
  title = "Towards fine-grained access control in health grids",
  author = "Simpson, A.~C. and Power, D.~J. and Slaymaker, M.~A. and Politou, E.~A.",
  year = "2005",
  booktitle = "Proceedings of the Ottawa Workshop on New Challenges in Access Control",
  month = "April",
}