Wittich, W. A. (1958). Audivisual materials: Their nature and use. Harper y Row.
Lua i Stíl Chicago (17ú heag.)Wittich, Walter A. Audivisual Materials: Their Nature and Use. New York: Harper y Row, 1958.
Lua MLA (9ú heag.)Wittich, Walter A. Audivisual Materials: Their Nature and Use. Harper y Row, 1958.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.