%0 Journal Article
%A Hardie, K. A.
%T Homotopy of Natural Transformations
%J Canadian journal of mathematics
%D 1970
%P 332-341
%V 22
%N 2
%U http://geodesic.mathdoc.fr/articles/10.4153/CJM-1970-041-2/
%R 10.4153/CJM-1970-041-2
%F 10_4153_CJM_1970_041_2