@article {fonda2013periodic, title = {Periodic bouncing solutions for nonlinear impact oscillators}, journal = {Advanced Nonlinear Studies}, volume = {13}, number = {1}, year = {2013}, pages = {179{\textendash}189}, publisher = {Advanced Nonlinear Studies, Inc.}, doi = {10.1515/ans-2013-0110}, author = {Alessandro Fonda and Andrea Sfecci} }