edited by Michael S. Lewis-Beck
Sage, 1993
Buku Referensi
Michael S. Lewis-Beck, editor
Sage Publications, 1993
Buku Referensi
Leabo, Dick A., author
Richard D. Irwin, 1968
Buku Teks
Kazmier, Leonard J., author
McGraw-Hill, 1984
Buku Teks
John Wiley and Sons, Inc., 1967
Buku Teks