edited by Michael S. Lewis-Beck
Sage, 1993
Buku Referensi
edited by William W. Hay, Myron J. Levin, Judith M. Sondheimer, Robin R. Deterding
McGraw-Hill, 2007
Buku Referensi
Sally B. Olds, Marcia L. London, Patricia A. Wieland Ladewig, Michele R. Davidson
Pearson Education, 2004
Buku Referensi
Myer Kutz
McGraw-Hill, 2011
Buku Teks
Barash, Paul G., author
Lippincott - Raven Publishers, 1997
Buku Referensi