1. Analysis and classification of a vowel database;Assmann;Canadian Acoustics,2008
2. Semi-Supervised Learning;Chapelle,2006
3. Maximum likelihood from incomplete data via the EM algorithm;Dempster;Royal Statistical Society,1977
4. Pattern Classification;Duda,2001
5. The estimation of the gradient of a density function, with applications in pattern recognition;Fukunaga;IEEE Transactions on Information Theory,1975