Vardaman, George T.
Auerbach Publishers, 1973
Buku Teks
Cohen, William A., author
American Management Association, 2006
eBooks
Muhammad Syafi`i Antonio, author
Tazkia Publishing, 2010
Buku Teks
Charam, Ram, author
Bhuana Ilmu Populer, 2008
Buku Teks
Deming, Vasudha Kathleen, author
McGraw-Hill, 2004
Buku Teks