%0 Journal Article
%A Goebel, K.
%T Convexity of balls and fixed-point theorems for mappings with nonexpansive square
%J Compositio Mathematica
%D 1970
%P 269-274
%V 22
%N 3
%I Wolters-Noordhoff Publishing
%U http://www.numdam.org/item/CM_1970__22_3_269_0/
%G en
%F CM_1970__22_3_269_0