Wittich, W. A., & Schuller, C. F. (1973). Instructional technology: Its nature and use (5th ed.). Harper & Row.
Cita Chicago (17th ed.)Wittich, Walter Arno, i Charles Francis Schuller. Instructional Technology: Its Nature and Use. 5th ed. New York: Harper & Row, 1973.
Cita MLA (8th ed.)Wittich, Walter Arno, i Charles Francis Schuller. Instructional Technology: Its Nature and Use. 5th ed. Harper & Row, 1973.
Atenció: Aquestes cites poden no estar 100% correctes.