%0 Journal Article
%A Wang, Genqiang
%A Cheng, Sui Sun
%T Even periodic solutions of higher order duffing differential equations
%J Czechoslovak Mathematical Journal
%D 2007
%P 331-343
%V 57
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/CMJ_2007__57_1_a24/
%G en
%F CMJ_2007__57_1_a24