Institute Kajian Dasar , 1996
Buku Teks
Palma, Refael
Prentice-Hall, 1949
Buku Teks SO
Coates, Austin
Oxford University Press, 1968
Buku Teks SO
Dita Putri Prameswari
Universitas Indonesia, 2011
UI - Tesis Open
Burgess, Peter H.
Graham Brash, 1983
Buku Referensi