@inproceedings{
 author = {Adam J. Lee and Jodie P. Boyer and Lars E. Olson and Carl A. Gunter},
 title = {Defeasible security policy composition for web services},
 booktitle = {FMSE '06: Proceedings of the fourth ACM workshop on Formal methods in security},
 year = {2006},
 isbn = {1-59593-550-9},
 pages = {45--54},
 location = {Alexandria, Virginia, USA},
 doi = {http://doi.acm.org/10.1145/1180337.1180342},
 publisher = {ACM Press},
 address = {New York, NY, USA},
 }