Cooper, Robert L., author
Cambridge University Press, 1989
Buku Teks
Morris, Robert, author
Columbia University Press , 1966
Buku Teks
Jones, Mari C, author
Routledge , 2006
Buku Teks
Moore, Wilbert E. (Wilbert Ellis), author
Prentice-Hall, 1963
Buku Teks
edited by Robert A. Nisbet
Blackwell, 1972
Buku Teks