Grady, W. E., Klapper, P., Gifford, J. C., Hoopes, F., & Hoopes, M. C. (1939). Good friends: A primer. Charles Scribner's Sons.
Lua i Stíl Chicago (17ú heag.)Grady, William E., Paul Klapper, Jane C. Gifford, Florence Hoopes, agus Margaret Campbell Hoopes. Good Friends: A Primer. New York ; Chicago ; Boston ; Atlanta ; Dallas ; San Francisco: Charles Scribner's Sons, 1939.
Lua MLA (8ú heag.)Grady, William E., et al. Good Friends: A Primer. Charles Scribner's Sons, 1939.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.