1. Ahn, G., Sandhu, R.: Role-based authorization constraints specification. Inf. Syst. Secur. 3(4), 207–226 (2000)
2. Ahn, G., Shin, M.: Role-based authorization constraints specification using object constraint language. In: Tenth IEEE International Workshops on Enabling Technologies: Infrastructure for Collaborative Enterprises, Massachusetts, pp. 157–165 (2001)
3. Ahn, G.J., Sandhu, R.: The rsl99 language for role-based separation of duty constraints. In: 4th ACM Workshop on Role-Based Access Control, Fairfax (1999), pp. 43–54
4. Barkley, J.F., Beznosov, K., Uppal, J.: Supporting relationships in access control using role based access control. In: Third ACM Workshop on Role Based Access Control, pp. 55–65 (1999)
5. Cao, J., et al.: Towards secure xml document with usage control. In: Web Technologies Research and Development - APWeb 2005, Berlin. Springer, Berlin (2005)