@InProceedings{ pretschner.ea:negotiation:2008, author = {A. Pretschner and T. Walter}, booktitle = {1st Intl. Workshop on Advances in Policy Enforcement}, language = {USenglish}, month = 3, note = {Keynote}, title = {Negotiation of Usage Control Policies - Simply the Best}, year = 2008, user = {pretscha} }