@article{MZM_1991_49_5_a5,
     author = {A. M. Vershik and O. A. Granichina},
     title = {Reduction of nonholonomic variation problems to isoperimetric ones and connections in principal bundles},
     journal = {Matemati\v{c}eskie zametki},
     pages = {37--44},
     publisher = {mathdoc},
     volume = {49},
     number = {5},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1991_49_5_a5/}
}