@article{INTG_1966_1_a9,
     author = {P. I. Shveikin},
     title = {Normal geometric objects of a~surface in an affine space},
     journal = {Itogi Nauki i Tekhniki. Seriya Problemy Geometrii. Trudy Geometricheskogo Seminara},
     pages = {331--423},
     publisher = {mathdoc},
     volume = {1},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/INTG_1966_1_a9/}
}