1. boyd, d.m., Ellison, N.B.: Social network sites: Definition, history, and scholarship. Journal of Computer-Mediated Communication 13(1), 210–230 (2008)
2. Barka, E.S., Sandhu, R.S.: Framework for role-based delegation models. In: Proceedings of the 16th Annual Computer Security Applications Conference (ACSAC 2000), New Orleans, Louisiana, USA (December 2000)
3. Crampton, J., Khambhammettu, H.: Delegation in role-based access control. International Journal of Information Security 7(2), 123–136 (2008)
4. Graham, G.S., Denning, P.J.: Protection: Principles and practices. In: Proceedings of the 1972 AFIPS Spring Joint Computer Conference, Alantic City, New Jersey, USA, May 1972, vol. 40, pp. 417–429 (1972)
5. Li, N., Tripunitara, M.V.: On safety in discretionary access control. In: Proceedings of the 2005 IEEE Symposium on Security and Privacy (S&P 2005), Oakland, California, USA, May 2005, pp. 96–109 (2005)