Yoon, Eun-Jun, Ein-Jung Lee, and Kee-Young Yoo. Cryptanalysis of Wang et al.?s Remote User Authentication Scheme Using Smart Cards In 5th International Conference on Information Technology: New Generations., 2008.

Yoon, Eun-Jun, Eun-Kung Ryu, and Kee-Young Yoo. "Further Improvement of an Efficient Password Based Remote User Authentication Scheme Using Smart Cards." IEEE Transactions on Consumer Electronics 50, no. 2 (2004).