@article{JRAM_1985__362_152766,
     author = {Andrew John Sommese and Joseph Lipman},
     title = {On blowing down projective spaces in singular varieties.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {51--62},
     publisher = {mathdoc},
     volume = {362},
     year = {1985},
     zbl = {0566.14007},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1985__362_152766/}
}