@article{VMUMM_1990_1_a12,
     author = {P. P. Bobrik},
     title = {Periodic solutions in a problem of a heavy rigid body with one fixed point},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {52--55},
     publisher = {mathdoc},
     number = {1},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1990_1_a12/}
}