A course in homological algebra [by] P. J. Hilton [and] U. Stammbach. Hilton, Peter, 1923-2010. Stammbach, Urs, joint author. Algebra, Homological. QA169 .H55 512 HIC Bibliography: p. [331]-332. New York, Springer-Verlag 1971 1971 1971 Text ix, 338 p. eng Graduate texts in mathematics, 4