%0 Journal Article
%A Walker, Marshall
%T Homotopy Pull-Backs and Applications to Duality
%J Canadian journal of mathematics
%D 1977
%P 45-64
%V 29
%N 1
%U http://geodesic.mathdoc.fr/articles/10.4153/CJM-1977-004-3/
%R 10.4153/CJM-1977-004-3
%F 10_4153_CJM_1977_004_3