%0 Journal Article
%T Letter
%J Canadian mathematical bulletin
%D 1962
%P 91-92
%V 5
%N 1
%U http://geodesic.mathdoc.fr/articles/10.1017/S0008439500026060/
%R 10.1017/S0008439500026060
%F 10_1017_S0008439500026060