@article{702354, title = {Hamiltonian systems with periodic nonlinearities}, booktitle = {Equadiff 7}, series = {GDML\_Books}, publisher = {BSB B.G. Teubner Verlagsgesellschaft}, address = {Leipzig}, year = {1990}, pages = {131-134}, zbl = {0721.58010}, url = {http://dml.mathdoc.fr/item/702354} }
Szulkin, A. Hamiltonian systems with periodic nonlinearities, dans Equadiff 7, GDML_Books, (1990), pp. 131-134. http://gdmltest.u-ga.fr/item/702354/