@article{ND_2013_9_1_a4,
     author = {Sergey V. Bolotin and Tatiana V. Popova},
     title = {On the motion of a mechanical system inside a rolling ball},
     journal = {Russian journal of nonlinear dynamics},
     pages = {51--58},
     publisher = {mathdoc},
     volume = {9},
     number = {1},
     year = {2013},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ND_2013_9_1_a4/}
}