%0 Journal Article %A Fawcett, Barry %T A Canonical Factorization for Graph Homomorphisms %J Canadian journal of mathematics %D 1977 %P 738-743 %V 29 %N 4 %U http://geodesic.mathdoc.fr/articles/10.4153/CJM-1977-077-3/ %R 10.4153/CJM-1977-077-3 %F 10_4153_CJM_1977_077_3