Henni Oktaviani
Fakultas Ilmu Pengetahuan Budaya Universitas Indonesia, 1999
UI - Skripsi Membership
Tahkur, Ramesh
Westview Press, 1986
Buku Referensi
edited by Gordon Greenwood and Norman Harper
F.W. Cheshire, 1957
Buku Teks SO
edited by Gordon Greenwood and Norman Harper
F.W. Chesire, 1968
Buku Teks SO
by J. Swiericzuk ... [and others]
Pitman, 1980
Buku Teks SO