@article{PORMA_1998__55_4_48260,
     author = {Minh\'os, Feliz},
     title = {Periodic solutions for a third order differential equation under conditions on the potential.},
     journal = {Portugaliae mathematica},
     pages = {475--484},
     publisher = {mathdoc},
     volume = {55},
     number = {4},
     year = {1998},
     zbl = {0923.34045},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1998__55_4_48260/}
}