Tuma, Nancy Brandon, author
Academic Press, 1984
Buku Teks
Cohen, Lillian, author
Prentice-Hall, 1955
Buku Teks
Goode, William J., author
McGraw-Hill, 1952
Buku Teks
MnMillen, Wyne
University of Chicago Press , 1951
Buku Teks
Hanushek, Eric A., author
Academic Press, 1977
Buku Teks