Book, W. F. (1932). Economy and technique of learning. D. C. Heath.
Lua i Stíl Chicago (17ú heag.)Book, William Frederick. Economy and Technique of Learning. Boston: D. C. Heath, 1932.
Lua MLA (8ú heag.)Book, William Frederick. Economy and Technique of Learning. D. C. Heath, 1932.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.