%0 Journal Article %A Kehrein, Achim %T Projective objects in the category of chain complexes %J Communications in Mathematics %D 1999 %P 33-38 %V 07 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/COMIM_1999__7_1_a2/ %G en %F COMIM_1999__7_1_a2