@InProceedings{bbgpr07:consumable,
  author = 	 {Kevin D. Bowers and Lujo Bauer and Deepak Garg and Frank Pfenning and Michael K. Reiter},
  title = 	 {Consumable credentials in logic-based access-control systems},
  booktitle =    {Proceedings of the 2007 Network & Distributed System Security Symposium},
  pages =        {143--157},
  month =        feb,
  year = 	 {2007},
  url =          {http://www.ece.cmu.edu/~lbauer/papers/2007/ndss2007-consumable.pdf},
  copyright =    {Internet Society},
  publisher =    {Internet Society},
}