Guillebaud, John
Churchill Livingstone, 1993
Buku Teks
edited by Cheryl Gamble
American Society for Training & Development, 2010
eBooks
Guillebaud, John
Oxford University Press, 1985
Buku Teks
Whitehead, Malcolm, author
Churchill Livingstone , 1992
Buku Teks
Gates, Rose A., author
Mosby Elsevier, 2008
Buku Teks