1. Bahl, L.R., de Souza, P.V., Gopalakrishnan, P.S., Nahamoo, D., Picheny, M.A.: Decision trees for phonological rules in continuous speech. In: ICASSP 1991, pp. 185–188. IEEE Computer Society, Washington, DC, USA (1991)
2. Young, S.J., Odell, J.J., Woodland, P.C.: Tree-based state tying for high accuracy acoustic modelling. In: Proceedings of the workshop on Human Language Technology. HLT 1994, pp. 307–312. ACL, Stroudsburg (1994)
3. Baker, J., Deng, L., Khudanpur, S., Lee, C.H., Glass, J., Morgan, N., O’Shaughnessy, D.: Updated MINDS report on speech recognition and understanding, Part 2 (DSP Education). IEEE Signal Processing Magazine 26(4), 78–85 (2009)
4. Prince, A., Smolensky, P.: Optimality Theory: Constraint Interaction in Generative Grammar. Blackwell, Oxford (1993/2004)
5. Young, S., Woodland, P.C.: State clustering in hidden Markov model-based continuous speech recognition. Computer Speech & Language 8(4), 369–383 (1994)