@article{DAN_1987_292_4_a7,
     author = {S. L. Ziglin},
     title = {The absence of an additional first integral in a problem of the},
     journal = {Doklady Akademii Nauk},
     pages = {804--807},
     publisher = {mathdoc},
     volume = {292},
     number = {4},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1987_292_4_a7/}
}