@article {1989,
	title = {On the number of families of periodic solutions of a Hamiltonian system near equilibrium. II.  (English. Italian summary)},
	journal = {Boll. Un. Mat. Ital. B (7)  3  (1989),  no. 3, 579-590},
	number = {SISSA;13/88/FM},
	year = {1989},
	publisher = {SISSA Library},
	url = {http://hdl.handle.net/1963/609},
	author = {Gianfausto Dell{\textquoteright}Antonio and Biancamaria D{\textquoteright}Onofrio}
}
