Bartholomew, David J., author
John Wiley & Sons, 1981
Buku Teks
Crano, William D., author
Lawrence Erlbaum Assossiate, 2002
Buku Teks
Hanushek, Eric A., author
Academic Press, 1977
Buku Teks
Goode, William J., author
McGraw-Hill, 1952
Buku Teks
by Claire Selltiz [and others]
Holt, Rinehart and Winston, 1959
Buku Teks