00297nam a2200109Ia 4500082001800000100002100018245007600039260004800115300001400163500000500177700000500182  a512bSt924.IC  aStrooker, Jan R.  aIntroduction to categories, homological algebras and sheaf cohomologyb  aCambridgebCambridge University Pressc1978  aix, 246p.  a  a