@article{DistUsageControl,
 author = {Alexander Pretschner and Manuel Hilty and David Basin},
 title = {Distributed usage control},
 journal = {Communications of the  ACM},
 volume = {49},
 number = {9},
 year = {2006},
 issn = {0001-0782},
 pages = {39--44},
 publisher = {ACM Press},
 address = {New York, NY, USA}
 }