Voir la notice de l'article provenant de la source Math-Net.Ru
@article{IVM_1991_3_a11, author = {V. L. Khatskevich}, title = {Solvability of a~periodic problem for a~nonlinear {Hamiltonian} system}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {61--70}, publisher = {mathdoc}, number = {3}, year = {1991}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1991_3_a11/} }
V. L. Khatskevich. Solvability of a~periodic problem for a~nonlinear Hamiltonian system. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 3 (1991), pp. 61-70. http://geodesic.mathdoc.fr/item/IVM_1991_3_a11/