@article{MZM_1987_41_4_a12,
     author = {Yu. A. Aminov},
     title = {Condition of holonomicity of characteristic directions of a submanifold},
     journal = {Matemati\v{c}eskie zametki},
     pages = {543--548},
     year = {1987},
     volume = {41},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1987_41_4_a12/}
}