@incollection{JM09, author = {H. L. Jonker and S. Mauw}, title = {Discovering the core security requirements of DRM systems by means of objective trees}, booktitle = {Handbook of Research on Secure Multimedia Distribution}, editor = {Shiguo Lian and Yan Zhang}, pages = {71--85}, publisher = {IGI Global}, isbn = {978-1-60566-263-3}, ee = {http://www.igi-global.com/chapter/discovering-core-security-requirements-drm/21308}, year = {2009} }