S. Seneff, E. Hurley, R. Lau, C. Pao, P. Schmid, and V. Zue. Proceedings of the 5th International Conference on Spoken Language Processing (ICSLP'98), Sydney, Australia, page 931-934. (1998)
J. Ponte, and B. Croft. SIGIR '98: Proceedings of the 21st annual international ACM SIGIR conference on Research and development in information retrieval, page 275--281. New York, NY, USA, ACM Press, (1998)
M. Piotrowski. Friedrich-Alexander-Universität Erlangen-Nürnberg, Institut für Germanistik, Abteilung für Computerlinguistik, Erlangen, Magisterarbeit, (1998)