Moore, David S.
W.H. Freeman, 2000
Buku Teks SO
Michael S. Lewis-Beck, editor
Sage Publications, 1993
Buku Referensi
Kaplan, Robert M.
Allyn and Bacon, 1987
Buku Teks SO
John Wiley and Sons, Inc., 1967
Buku Teks SO
Hoel, Paul Gerhard, 1905-
Wiley, 1982
Buku Teks SO