@article{DAN_1986_287_5_a12,
     author = {V. A. Chernyatin},
     title = {Necessary and sufficient conditions for existence of the classical},
     journal = {Doklady Akademii Nauk},
     pages = {1080--1083},
     year = {1986},
     volume = {287},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1986_287_5_a12/}
}