Citazione Stile APA (7a Edizione)

Tough, A. M. (1979). The adult's learning projects: A fresh approach to theory and practice in adult learning (2d ed.). Learning Concepts.

Citazione stile Chigago Style (17a edizione)

Tough, Allen M. The Adult's Learning Projects: A Fresh Approach to Theory and Practice in Adult Learning. 2d ed. Austin, Tex.: Learning Concepts, 1979.

Citatione MLA (8a ed.)

Tough, Allen M. The Adult's Learning Projects: A Fresh Approach to Theory and Practice in Adult Learning. 2d ed. Learning Concepts, 1979.