Edward, David V., author
Holt, Rinehart and Winston, 1969
Buku Teks
Bechhoefer, Bernhard G., author
Brookings Institution, 1961
Buku Teks
Brzezinski, Zbigniev K., author
Macmillan Publishing Company, 1993
Buku Teks
edited by George Gerbner, Richard B. Byrne
John Wiley & Sons, 1981
Buku Teks
Russel, Fox Hon, author
Covendish Publishing Limited, 2000
Buku Teks