@article{DAN_1975_224_2_a1,
     author = {S. A. Bogatyi},
     title = {On the preservation of shapes under mappings},
     journal = {Doklady Akademii Nauk},
     pages = {261--264},
     publisher = {mathdoc},
     volume = {224},
     number = {2},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1975_224_2_a1/}
}