@article{SM_2010_201_7_a4,
     author = {Yu. L. Sachkov},
     title = {Maxwell strata and symmetries in the problem of optimal rolling of a~sphere over a~plane},
     journal = {Sbornik. Mathematics},
     pages = {1029--1051},
     publisher = {mathdoc},
     volume = {201},
     number = {7},
     year = {2010},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2010_201_7_a4/}
}