@article{ARM_2006__42_3_a0,
     author = {Filippakis, Michael E. and Papageorgiou, Nikolaos S.},
     title = {A nonlinear periodic system with nonsmooth potential of indefinite sign},
     journal = {Archivum mathematicum},
     pages = {205--213},
     publisher = {mathdoc},
     volume = {42},
     number = {3},
     year = {2006},
     mrnumber = {2260378},
     zbl = {1164.34404},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ARM_2006__42_3_a0/}
}