D. Zhang, K. Ramamohanarao, and T. Ebringer. SACMAT '07: Proceedings of the 12th ACM symposium on Access control models and technologies, page 139--144. New York, NY, USA, ACM, (2007)
J. Vaidya, V. Atluri, and J. Warner. CCS '06: Proceedings of the 13th ACM conference on Computer and communications security, page 144--153. New York, NY, USA, ACM, (2006)
G. Neumann, and M. Strembeck. SACMAT '02: Proceedings of the seventh ACM symposium on Access control models and technologies, page 33--42. New York, NY, USA, ACM, (2002)