9Crampton J, Martin K, Wild P. On key assignment for hierarchical access control. In: Guttan J, ed, Proc. of the 19th IEEE Computer Security Foundations Workshop--CSFW 2006. Venice: IEEE Computer Society Press, 2006. 5-7.
10Damiani E, De S, Vimercati C, Foresti S, Jajodia S, Paraboschi S, Samarati P. An experimental evaluation of multi-key strategies for data outsourcing. In: Venter HS, Eloff MM, Labuschagne L, Eloff JHP, Solms RV, eds. New Approaches for Security, Privacy and Trust in Complex Environments, Proc. of the IFIP TC-11 22nd Int'l Information Security Conf. Sandton: Springer-Verlag, 2007. 395-396.
