David H. Laidlaw, Kurt W. Fleischer, and Alan H. Barr. Partial-Volume Bayesian Classification of Material Mixtures in MR Volume Data Using Voxel Histograms. IEEE Transactions on Medical Imaging. Also reprinted in 2000 yearbook of Medical Informatics, International Medical Informatics Assoc., Shattauer, 2000., 17(1):74-86, February 1998. (pdf) (bibtex: Laidlaw-1998-PVB).