Clark, Burton R., author
University of California Press, 1968
Buku Teks
Knowles, Malcolm S., author
Cambridge University Press, 1980
Buku Teks
Hinzen, Heribert, author
Adult Education, 1982
Buku Teks
Knowles, Malcolm S., author
Routledge, 2015
Buku Teks
McGivney, Veronica
The National Institute of Adult Continuing Education, 1991
Buku Teks