Tough, A. M. (1979). The adult's learning projects: A fresh approach to theory and practice in adult learning (2d ed.). Learning Concepts.
Čikaški stil citiranja (17. izdanje)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.
MLA način citiranja (8. izdanje)Tough, Allen M. The Adult's Learning Projects: A Fresh Approach to Theory and Practice in Adult Learning. 2d ed. Learning Concepts, 1979.
Upozorenje: Ovi citati možda nisu uvijek 100% točni.