V. Benjumea, S. Choi, J. Lopez, and M. Yung. Cryptology and Network Security, volume 4856 of Lecture Notes in Computer Science, page 265-281. Springer, (2007)
J. Camenisch, and E. Herreweghen. CCS '02: Proceedings of the 9th ACM conference on Computer and communications security, page 21-30. New York, NY, USA, ACM, (2002)