%0 Journal Article
%A Matzeu, M.
%A Girardi, M.
%T On periodic solutions of a class of second order nonautonomous systems with nonhomogeneous potentials indefinite in sign
%J Rendiconti del Seminario Matematico della Università di Padova
%D 1997
%P 193-210
%V 97
%I Seminario Matematico of the University of Padua
%U http://archive.numdam.org/item/RSMUP_1997__97__193_0/
%G en
%F RSMUP_1997__97__193_0