edited by Richard Edwards
Routledge, 1993
Buku Teks
Knowles, Malcolm S., author
Cambridge University Press, 1980
Buku Teks
Knowles, Malcolm S., author
Routledge, 2015
Buku Teks
Lucas, Robert W., author
ASTD Press, 2010
Buku Teks
Parrish, Betsy, author
McGraw-Hill , 2004
Buku Teks