Não informado. (1960). Educators Guide to Free Science Materials. Educators Progress Service.
Lua i Stíl Chicago (17ú heag.)Não informado. Educators Guide to Free Science Materials. Randolph, Wis: Educators Progress Service, 1960.
Lua MLA (8ú heag.)Não informado. Educators Guide to Free Science Materials. Educators Progress Service, 1960.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.