Peters, Gary L., author
Kendall/Hunt, 1983
Buku Teks
Weeks, John R.
Wadsworth, 1986
Buku Teks
Heer, David M., author
Prentice-Hall, 1975
Buku Teks
edited by Philip M. Hauser and Otis Dudley Duncan
The University of Chicago Press, 1959
Buku Teks
Goldscheider, Calvin, author
Litle Brown, 1971
Buku Teks