1. Styles, B. C., thesis, Cambridge Univ. (1973).
2. Askenfelt, A., Quarterly Progress and Status Report, Speech Transmission Laboratory, Royal Institute of Technology, Stockholm, 1, 1 (1976).
3. Longuet-Higgins, H. C., and Steedman, M. J., Machine Intelligence, 6, 221 (1971).
4. Steedman, M. J., thesis, Univ. Edinburgh (1973).
5. Rameau, M., Traité de l'harmonie reduite a des principes naturels (1721).