@article{DAN_1961_140_4_a7,
     author = {P. I. Petrov},
     title = {The fundamental problem of {non-Riemannian} geometry in a binary region},
     journal = {Doklady Akademii Nauk},
     pages = {766--768},
     publisher = {mathdoc},
     volume = {140},
     number = {4},
     year = {1961},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1961_140_4_a7/}
}