Ellis, Charles D.
Irwin Professional Publishing , 1993
Buku Teks
Cohen, Jerome B.
Richard D. Irwin, 1987
Buku Teks
Haugen, Robert A.
Prentice-Hall, 1997
Buku Teks
Elton, Edwin J.
John Wiley & Sons, 1984
Buku Teks
Haugen, Robert A.
Prentice-Hall, 1990
Buku Teks