Gelfand, M.A., author
Unesco, 1971
Buku Teks
Moore, Brian
General Publishing, 1967
Koleksi Publik
Long, Lori, author
[American Society for Training and Development Press, American Society for Training and Development Press], 2000
eBooks
Hough, Michael, author
Research Office Research and Statistics Directorate, 1998
Buku Teks
edited by Meredith L. Weiss
Institute of South East Asia Studies, 2014
eBooks