@article{DAN_1966_171_4_a15,
     author = {Bl. Dolapchiev},
     title = {Nielsen--Zenov's equations and their application to nonholonomic systems with non-linear connections},
     journal = {Doklady Akademii Nauk},
     pages = {820--822},
     publisher = {mathdoc},
     volume = {171},
     number = {4},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1966_171_4_a15/}
}