Cita APA (7a ed.)

Leedham, J., & Unwin, D. (1971). Programmed learning in the schools (2nd ed.). Longman.

Cita Chicago Style (17a ed.)

Leedham, John, y Derick Unwin. Programmed Learning in the Schools. 2nd ed. London: Longman, 1971.

Cita MLA (9a ed.)

Leedham, John, y Derick Unwin. Programmed Learning in the Schools. 2nd ed. Longman, 1971.