Não informado. (1989). Adults Learning. National Institute of Adult Continuing Education.
Chicago-Zitierstil (17. Ausg.)Não informado. Adults Learning. Leicester, Inglaterra: National Institute of Adult Continuing Education, 1989.
MLA-Zitierstil (8. Ausg.)Não informado. Adults Learning. National Institute of Adult Continuing Education, 1989.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.