L. Silva, and L. Jayaratne. Applications of Digital Information and Web Technologies, 2009. ICADIWT '09. Second International Conference on the, page 446-451. (August 2009)
P. Cimiano, and J. Völker. Proceedings of the 10th International Conference on Applications of Natural Language to Information Systems (NLDB), volume 3513 of Lecture Notes in Computer Science, page 227-238. Alicante, Spain, Springer, (June 2005)