Blalock, Hubert M., author
McGraw-Hill, 1972
Buku Teks
Johnson, Robert, author
PWS-Kent, 1984
Buku Teks
Mann, Prem S, author
John Wiley & Sons, 2013
Buku Teks
Haber, Audrey, author
Addison-Wesley , 1970
Buku Teks
Michael S. Lewis-Beck, editor
Sage Publications, 1993
Buku Referensi