Levi, H. (1960). Foundations of geometry and trignometry. Prentice Hall.
Lua i Stíl Chicago (17ú heag.)Levi, Howard. Foundations of Geometry and Trignometry. Englewood Cliffs: Prentice Hall, 1960.
Lua MLA (9ú heag.)Levi, Howard. Foundations of Geometry and Trignometry. Prentice Hall, 1960.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.