Oesterle, Dale A.
West Publishing Co., 1991
Buku Teks
Kintner, Earl W.
N.Y. Macmillan, 1971
Buku Teks
edited by Claire A. Hill, James L. Krusemark
UK Edward Elgar Publishing, 2016
Buku Teks
Partner, Simon
New Jersey, Prentice Hall1991,
Buku Referensi
Weston, John Fred, 1916-
McGraw-Hill, 2001
Buku Teks