@article{DAN_1965_162_6_a5,
     author = {Yu. I. Ermakov},
     title = {On the invariant framing of some surfaces of a special kind in projective space},
     journal = {Doklady Akademii Nauk},
     pages = {1234--1237},
     publisher = {mathdoc},
     volume = {162},
     number = {6},
     year = {1965},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1965_162_6_a5/}
}