@article{DAN_1973_210_4_a9,
     author = {V. V. Rumyantsev},
     title = {Chetaev{\textquoteright}s principle},
     journal = {Doklady Akademii Nauk},
     pages = {787--790},
     publisher = {mathdoc},
     volume = {210},
     number = {4},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1973_210_4_a9/}
}