%0 Journal Article %A Piacenza, Robert J. %T Homotopy Theory of Diagrams and CW-Complexes Over a Category %J Canadian journal of mathematics %D 1991 %P 814-824 %V 43 %N 4 %U http://geodesic.mathdoc.fr/articles/10.4153/CJM-1991-046-3/ %R 10.4153/CJM-1991-046-3 %F 10_4153_CJM_1991_046_3