@article{PM_1997_1997_1_a9,
     author = {Chicone, Carmen},
     title = {Toros invariantes para osciladores perturbados peri\'odicamente.},
     journal = {Publicacions matem\`atiques},
     pages = {57-83},
     publisher = {mathdoc},
     volume = {41},
     number = {1},
     year = {1997},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PM_1997_1997_1_a9/}
}