Zassenhaus, Hans What is an angle? (English) Zbl 0056.38601 Am. Math. Mon. 61, 369-378 (1954). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 1 ReviewCited in 2 Documents Keywords:Foundations of geometry, noneuclidean geometry PDFBibTeX XMLCite \textit{H. Zassenhaus}, Am. Math. Mon. 61, 369--378 (1954; Zbl 0056.38601) Full Text: DOI