H. Traunmüller. Experiments in speech processes, volume XII of Phonetic Experimental Research at the Institute of Linguistics, The Institute of Linguistics, University of Stockholm, Stockholm, (1991)
M. Collins. Proceedings of the ACL-02 conference on Empirical methods in natural language processing - Volume 10, page 1--8. Stroudsburg, PA, USA, Association for Computational Linguistics, (2002)
M. Collins. Proceedings of the eighth conference on European chapter of the Association for Computational Linguistics, page 16--23. Stroudsburg, PA, USA, Association for Computational Linguistics, (1997)