Crego, Edwin T., author
[American Management Association;, ], 1995
eBooks
Westwood, John, author
Gramedia, 2006
Buku Teks
Berry, Ralph, author
Routledge, 1994
Buku Teks
Murray, Rowena
Open University Press, 2002
Buku Teks
Vallins, G.H.
Andrew Deutsch, 1952
Buku Teks