Zastrow, Charles, author
Buku Teks
Zastrow, Charles, author
Brooks/Cole, 1996
Buku Teks
Hicks, John R., author
The Clarendon Press, 1952
Buku Teks
Blalock, Hubert M., author
Prentice-Hall, 1970
Buku Teks
Labovitz, Sanford, author
McGraw-Hill, 1971.
Buku Teks