D. Pisanelli, M. Battaglia, and C. Lazzari. SoMeT, volume 161 of Frontiers in Artificial Intelligence and Applications, page 485-493. IOS Press, (2007)
F. Bergenti, L. Lazzari, M. Mari, and A. Poggi. WEBIST (Selected Papers), volume 1 of Lecture Notes in Business Information Processing, page 204-213. Springer, (2006)