@article{DE_1993_29_10_a13,
     author = {M. B. Sheftel},
     title = {Higher integrals and symmetries of {semi-Hamiltonian} systems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1782--1795},
     year = {1993},
     volume = {29},
     number = {10},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1993_29_10_a13/}
}