Text ( visual ) : unmediated Rudiments of plane affine geometry / P. Scherk and R. Lingenberg. -- Toronto ; Buffalo : University of Toronto Press , c1975. -- viii, 110, [4] p. : ill. ; 24 cm. -- (Mathematical expositions ; no. 20). -- Bibliography: p. [111] ; Includes index. -- ISBN 0802021514 ; (BA12111909) ; https://ci.nii.ac.jp/ncid/BA12111909 Author Heading(s): Scherk, Peter ; Lingenberg, Rolf. -- Classification(s): LCC : QA477 ; DC : 516/.4. -- Subject Heading(s): LCSH : Geometry, Affine