Sachs, Hans, 1942- Ebene isotrope Geometrie/ Hans Sachs. - Braunschweig: F. Vieweg, 1987. - vii, 198 p.: ill.; 23 cm. Bibliography: p. 191-198. ISBN: 3528084545 LCCN: 88135013 //r972 Subjects--Topical Terms: Geometry, Non-Euclidean.Geometry, Differential. Dewey Class. No.: 516.9 / S121e