%0 Journal Article
%A Doan The Hieu
%A Tran Le Nam
%T On the four vertex theorem in planes with
 radial density $e^{\varphi(r)}$
%J Colloquium Mathematicum
%D 2008
%P 169-174
%V 113
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/articles/10.4064/cm113-1-10/
%R 10.4064/cm113-1-10
%G en
%F 10_4064_cm113_1_10