Hardgrave, Robert L., author
Harcourt, Brace, 1970
Buku Teks
Hardgrave, Robert L., author
Harcourt College, 2000
Buku Teks
Sharan, P.
Metropolitan, 1984
Buku Teks
Guha, Amalendu
People's Publishing House, 1988
Buku Teks
Weiner, Myron, author
The University of Chicago Press , 1962
Buku Teks