@article{DAN_1962_146_4_a6,
     author = {V. S. Malakhovskii},
     title = {On a class of congruences of second-order curves with a degenerate focal surface},
     journal = {Doklady Akademii Nauk},
     pages = {765--766},
     publisher = {mathdoc},
     volume = {146},
     number = {4},
     year = {1962},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1962_146_4_a6/}
}