@article{FAA_1997_31_2_a14,
     author = {B. Z. Shapiro},
     title = {Normal {Forms} of the {Whitney} {Umbrella} with {Respect} to the {Contact} {Group} {Preserving} a {Cone}},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {91--94},
     publisher = {mathdoc},
     volume = {31},
     number = {2},
     year = {1997},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_1997_31_2_a14/}
}