00311nam a2200121 a 450000500170000008200160001710000220003324500400005526000320009530000220012763000240014963000160017320251203091201.0  a512.55bROT  aRotman, Joseph G.  aIntroduction to homological algebra  aAcademic publicationsc1979  a376p.b22cm.cHB.  aHomological algebra  aMathematics