@article{DAN_1957_115_4_a7,
     author = {S. I. Savel'ev},
     title = {Surfaces with plane generatrices along which the tangent plane is constant},
     journal = {Doklady Akademii Nauk},
     pages = {663--665},
     publisher = {mathdoc},
     volume = {115},
     number = {4},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_115_4_a7/}
}