@article{SM_1999_190_7_a0,
     author = {I. V. Arzhantsev},
     title = {Contractions of affine spherical varieties},
     journal = {Sbornik. Mathematics},
     pages = {937--954},
     publisher = {mathdoc},
     volume = {190},
     number = {7},
     year = {1999},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1999_190_7_a0/}
}