edited by David Bridges
Routledge, 1997
Buku Referensi
Association for Educational and Training Technology; editor, C. W. Osborne
Kaogan Page, 1994
Buku Referensi
editors, Charles Antaki, Chris Brewin
Academic Press, 1982
Buku Teks
Eson, Morris E.
Holt, Rinehart and Winston, 1964
Buku Teks
Jackman, Hilda L., author
Wadsworth and Cengage Learning, 2012
Buku Teks