@article{PM_1997_1997_1_a7,
     author = {Delshams, Amadeu and Mir, Arnau},
     title = {Series psi de campos vectoriales cuadr\'aticos en el plano.},
     journal = {Publicacions matem\`atiques},
     pages = {101-125},
     year = {1997},
     volume = {41},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PM_1997_1997_1_a7/}
}