2. Auflage von 1984 (Langs Buch gilt als Standardwerk. Aus der Besprechung in den Notices of the American Mathematical Society: "Lang's Algebra changed the way graduate algebra is taught, retaining classical topics but introducing language and ways of thinking from category theory and homological algebra. It has affected all subsequent graduate-level algebra books.")
pnas.org
Saunders Mac Lane: The PNAS way back then. Gemeint ist Eilenberg-MacLane: Natural isomorphisms in group theory. Proc. Natl. Acad. Sci. USA 1942, Nr. 28, S. 537–543.
