1. Second order nonautonomous systems with symmetric potential changing sign;Antonacci;Rend. Mat. Appl.,1998
2. Sobolev Spaces;Adams,1975
3. Non-differentiable functionals and applications to elliptic problems with discontinuous nonlinearities;Bonanno;J. Differential Equations,2008
4. Multiplicity results for Sturm–Liouville boundary value problems;Bonanno;Appl. Math. Comput.,2009
5. Periodic solutions for a class of second-order Hamiltonian systems;Bonanno;Electron. J. Differential Equations,2005