Crano, William D.
Lawrence Erlbaum Assossiate, 2002
Buku Teks
Goode, William J.
McGraw-Hill, 1952
Buku Teks
by Claire Selltiz [and others]
Holt, Rinehart and Winston, 1959
Buku Teks
Black, James A.
John Wiley & Sons, 1976
Buku Teks
Judd, Charles M.
Methuen, 1991
Buku Teks