C. Fernández Tena, P. Baiget, X. Roca, and J. Gonzàlez. KI 2007: Advances in Artificial Intelligence, volume 4667 of Lecture Notes in Artificial Intelligence, Springer, Berlin, (2007)
M. Phillips, J. Nguyen, and A. Mischke. Advances in Speech Recognition: Mobile Environments, Call Centers and Clinics, chapter 3, Springer, New York, (2010)