(1930). Projective geometry, by John Wesley Young.
Lua i Stíl Chicago (17ú heag.)Projective Geometry, by John Wesley Young. 1930.
Lua MLA (9ú heag.)Projective Geometry, by John Wesley Young. 1930.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.