Arblaster, Anthony
Open University Press, 1987
Buku Teks
Schulz, Ernest B
[publisher not identified], 1956
Buku Teks
Mackie, Gerry
Cambridge University Press, 2003
Buku Teks
Eisenstadt, Shmuel Noah
The Woodrow Lilson Center Press, 1999
Buku Teks
Lindsay, A.D.
Oxford University Press, 1948
Buku Teks