@article{DAN_1970_190_2_a6,
     author = {I. S. Ovchinnikov},
     title = {Certain properties of plane and spatial mappings},
     journal = {Doklady Akademii Nauk},
     pages = {276--279},
     publisher = {mathdoc},
     volume = {190},
     number = {2},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1970_190_2_a6/}
}