Welchons, A. M., & Krickenberger, W. R. (1940). Teachers´ Key: To plane geometry. Ginn and Company.
Lua i Stíl Chicago (17ú heag.)Welchons, A. M., agus W. R. Krickenberger. Teachers´ Key: To Plane Geometry. Ginn and Company, 1940.
Lua MLA (9ú heag.)Welchons, A. M., agus W. R. Krickenberger. Teachers´ Key: To Plane Geometry. Ginn and Company, 1940.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.