D. Sonntag, and M. Möller. Proceedings of the International Conference on Knowledge Management and Information Sharing (KMIS), Madeira, Portugal, (2009)
H. Pon-Barry, F. Weng, and S. Varges. Proceedings of Interspeech 2006---ICSLP: 9th International Conference on Spoken Language Processing, Pittsburgh, PA, USA, page 1930-1933. (2006)