Jacob, Herbert, 1933-, author
McGraw-Hill, 1975
Buku Teks
Easton, David, author
John Wiley & Sons, 1965
Buku Teks
Dahl, Robert A., 1915-2014, author
Prentice Hall of India, 1976
Buku Teks
edited by James C. Charlesworth
The Free Press, 1968
Buku Teks
Dahl, Robert A., 1915-2014, author
Prentice-Hall, 1978
Buku Teks