Brogan, D.W. (Denis William)
Oxford University Press, 1950
Buku Teks
Ludwig, Emil, 1881-1948
Garden City Publishing, 1941
Buku Teks SO
Indra Hajar Aryanto H.
Fakultas Ilmu Pengetahuan Budaya Universitas Indonesia, 2001
UI - Skripsi Membership
Sherwood, Robert E.
Bantam Books, 1950
Buku Teks SO
Kingdon, Frank
Arco Publishing, 1944
Buku Teks SO