Delphos, William, 1951-
Business Expert Press, 2012
Buku Teks
Patel, Alpesh B
Palgrave Macmillan, 2005
Buku Teks
Morrison, Herbert
Oxford University Press, 1960
Buku Teks
edited by Alan F. Westin
W.W. Norton, 1961
Buku Teks
Slayden, Ellen Maury
New York: Harper & Row Publishers, [c1963]
Buku Teks