Wolfgang und Johann Bolyai geometrische Untersuchungen. Mit Unterstützung der Ungarischen Akademie der Wissenschaften hrsg. von Paul Stäckel
A German-language scholarly edition of the geometrical writings of Farkas and János Bolyai, edited by Paul Stäckel with support from the Hungarian Academy of Sciences and issued by Teubner in Leipzig in 1913 for mathematicians studying non-Euclidean geometry. The figures are fine line diagrams: labelled rays from a common point, solid and dashed arcs, marked angles and Greek and Fraktur letters, useful as sparse geometric linework.
