Lobachevskii, N. I. 1792-1856. Geometrical researches on the theory of parallels/ by Nicholas Lobatschewsky ; translated from the original by George Bruce Halsted. - Austin: University of Texas Press, 1892. - 50 p.: diagrs.; 23 cm. On cover: Bulletin of the University of Texas. Photocopy. Austin, Tex. : BookLab, 1996. 25 cm. Subjects--Topical Terms: Geometry, Non-Euclidean. Dewey Class. No.: 516.1 / L796g