1. M. Reid, ?Minimal models of canonical 3-folds,? Kyoto Univ. (1981).
2. Sh. Mori, ?Threefolds whose canonical bundles are not numerically effective,? Proc. Nat. Acad. Sci. USA,77, No. 7, 3125?3126 (1980).
3. M. Reid, ?Canonical 3-folds,? in: Journees de Geometrie Algebrique a Angers (July 1979), A. Beauville (ed.), Alpen aan den Rijn, Rockville (1980).
4. A. Durfee, ?Fifteen characterizations of rational double-points and simple critical points,? l'Enseignement Math.,25, 131?163 (1979).
5. V. I. Danilov, ?Geometry of toric varieties,? Usp. Mat. Nauk,33, No. 2, 85?134 (1978).