@article{JRAM_1991__417_153328,
     author = {Jaroslaw Wisniewski},
     title = {On contractions of extremal rays of {Fano} manifolds.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {141--158},
     publisher = {mathdoc},
     volume = {417},
     year = {1991},
     zbl = {0721.14023},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1991__417_153328/}
}