Ross, Lloyd
Macmillan, 1977
Buku Teks SO
Serle, Geoffrey
Melbourne University Press in association with Monash University, 1982
Buku Referensi
Craven, Paul R.
Dickenson Publishing, 1968
Buku Teks SO
Peeters, Benoît, 1956-
Polity Press, 2013
Buku Teks SO
Berg, A.Scott
Riverhead Books, 1989
Buku Teks