Stockwin, J.A.A.
Weidenfeld and Nicolson, 1975
Buku Teks SO
Richardson, Bradley M.
Harper Collins, 1984
Buku Teks SO
Langdon, Frank
Little, Brown and Company, 1967
Buku Teks SO
Bagus Fitrian Yudoprakoso
Fakultas Ilmu Sosial dan Ilmu Politik Universitas Indonesia, 2013
UI - Skripsi Membership
Sales, Rosemary
Routledge, 1997
Buku Teks SO