@article{DAN_1974_216_2_a4,
     author = {M. M. Lavrent'ev and V. R. Kireitov},
     title = {On a class of mappings of bisurfaces in three-dimensional space},
     journal = {Doklady Akademii Nauk},
     pages = {259--260},
     publisher = {mathdoc},
     volume = {216},
     number = {2},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1974_216_2_a4/}
}