Kennedy, Paul M
Vintage Books, 1993
Buku Teks
Kennedy, J.
Melbourne University Press, 1968
Buku Teks
Barnes, John A., author
American Management Association, 2005
eBooks
McKercher, Asa, author
Oxford University Press, 2016
eBooks
Schlesinger, Arthur Meier, author
Fawcett Publications, 1965
Buku Teks