Paris, Bernard J.
Indiana University Press, 1974
Buku Teks SO
Larson, Jil
Cambridge University Press, 2009
eBooks
edited by Patrick Brantlinger and William B. Thesing
Blackwell, 2002
Buku Referensi
Richard Saptenno
Fakultas Ilmu Pengetahuan Budaya Universitas Indonesia, 1987
UI - Skripsi Membership
Hanson, Clare
Macmillan, 1985
Buku Teks SO