TY  - JOUR
AU  - Yujiro Kawamata
TI  - Small contractions of four dimensional algebraic manifolds.
JO  - Mathematische Annalen
PY  - 1989
SP  - 595
EP  - 600
VL  - 284
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MAN_1989__284_4_164574/
ID  - MAN_1989__284_4_164574
ER  -