%0 Journal Article
%A PL. Kannappan
%T A  note on cosine functional equation for groups
%J Matematički vesnik
%D 1971
%P 317 
%V 23
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MV_1971_23_1_a38/
%F MV_1971_23_1_a38