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Fonda A, Klun G, Sfecci A. Periodic solutions of nearly integrable Hamiltonian systems bifurcating from infinite-dimensional tori. NONLINEAR ANALYSIS [Internet]. 2020  . Available from: https://doi.org/10.1016/j.na.2019.111720

Fonda A, Sfecci A. Periodic bouncing solutions for nonlinear impact oscillators. Advanced Nonlinear Studies. 2013  ;13:179?189.

Fonda A, Sfecci A. Periodic solutions of a system of coupled oscillators with one-sided superlinear retraction forces. Differential Integral Equations [Internet]. 2012  ;25:993?1010. Available from: https://projecteuclid.org:443/euclid.die/1356012248