Gans, D. (1973). An Introduction to non-Euclidean geometry. Academic Press.
Chicago Style aipamenaGans, David. An Introduction to Non-Euclidean Geometry. New York: Academic Press, 1973.
MLA aipamenaGans, David. An Introduction to Non-Euclidean Geometry. Academic Press, 1973.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.