Cita APA (7th ed.)

Sommerville, D. M. Y. (1958). The elements of non-Euclidean geometry. Dover.

Cita Chicago (17th ed.)

Sommerville, D. M. Y. The Elements of Non-Euclidean Geometry. New York: Dover, 1958.

Cita MLA (8th ed.)

Sommerville, D. M. Y. The Elements of Non-Euclidean Geometry. Dover, 1958.