Althaus, Scott L., author
Cambridge University Press, 2003
Buku Teks
Ginneken, Jaap van
Lawrence Erlbaum associates, 2002
Buku Teks
Butler, Rick
Doubleday & Company, Inc, 1978
Buku Teks
Ginneken, Jaap van
Lawrence Erlbaum associates, 1938
Buku Teks
Katz, Elihu, author
Free Press, 1964
Buku Teks