MacLane, Saunders Extensions and obstructions for rings. (English) Zbl 0081.03303 Ill. J. Math. 2, 316-345 (1958). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 2 ReviewsCited in 25 Documents Keywords:rings, modules, fields PDFBibTeX XMLCite \textit{S. MacLane}, Ill. J. Math. 2, 316--345 (1958; Zbl 0081.03303)