DeMello, Jim, author
McGraw-Hill, 2003
Buku Teks
by David F. Scott ... [and others]
Prentice-Hall, 1993
Buku Teks
Hamilton, Robert W.
St. Paul, Minn, 1989
Buku Teks
Engler, George N., author
Business Publications , 1982
Buku Teks
Hamilton, Robert W., author
West Publishing, 1984
Buku Teks