@article {2006,
	title = {Quasi-periodic solutions of completely resonant forced wave equations},
	journal = {Comm. Partial Differential Equations 31 (2006) 959 - 985},
	number = {SISSA;106/2004/M},
	year = {2006},
	abstract = {We prove existence of quasi-periodic solutions with two frequencies of completely resonant, periodically forced nonlinear wave equations with periodic spatial boundary conditions. We consider both the cases the forcing frequency is: (Case A) a rational number and (Case B) an irrational number.},
	doi = {10.1080/03605300500358129},
	url = {http://hdl.handle.net/1963/2234},
	author = {Massimiliano Berti and Michela Procesi}
}
@article {2005,
	title = {Quasi-periodic oscillations for wave equations under periodic forcing},
	journal = {Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 16 (2005), no. 2, 109-116},
	year = {2005},
	publisher = {Accademia Nazionale dei Lincei},
	url = {http://hdl.handle.net/1963/4583},
	author = {Massimiliano Berti and Michela Procesi}
}
