Lytle, Clifford M.
The University of Arizona, 1970
Buku Teks
edited by Burke Marshall
United States International Communication Agency, 1982
Buku Teks
Scigliano, Robert
The Free Press, 1971
Buku Teks
Agresto, John
Cornell University Press, 1984
Buku Teks
edited by Burke Marshall
National Public Radio, 1982
Buku Teks