@article{RSMUP_1990__83__183_0,
     author = {Beir\~ao da Veiga, H.},
     title = {Periodic solutions for a class of autonomous hamiltonian systems},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {183--192},
     publisher = {Seminario Matematico of the University of Padua},
     volume = {83},
     year = {1990},
     mrnumber = {1066440},
     zbl = {0709.34035},
     language = {en},
     url = {http://www.numdam.org/item/RSMUP_1990__83__183_0/}
}