Cita APA (7th ed.)

Wittich, W. A., & Schuller, C. F. (1957). Audio-visual materials: Their nature and use (2a. ed.). Harper & Brothers.

Cita Chicago (17th ed.)

Wittich, Walter Arno, i Charles Francis Schuller. Audio-visual Materials: Their Nature and Use. 2a. ed. Nueva York: Harper & Brothers, 1957.

Cita MLA (9th ed.)

Wittich, Walter Arno, i Charles Francis Schuller. Audio-visual Materials: Their Nature and Use. 2a. ed. Harper & Brothers, 1957.