Browne, G.S., author
F.W. Chesire, 1960
Buku Teks
edited by Bernard Berelson
Voice of America, 1975
Buku Teks
Clarke, John I., author
Pergamon Press, 1979
Buku Teks
Demko, George J., author
McGraw-Hill, 1970
Buku Teks
Plane, David A., author
John Wiley & Sons, 1994
Buku Teks