@article {2001, title = {Multiplicity results for some nonlinear Schrodinger equations with potentials}, journal = {Arch. Ration. Mech. An., 2001, 159, 253}, number = {SISSA;108/00/AF}, year = {2001}, publisher = {SISSA Library}, doi = {10.1007/s002050100152}, url = {http://hdl.handle.net/1963/1564}, author = {Antonio Ambrosetti and Andrea Malchiodi and Simone Secchi} }