Snow, Edgar
The World Publishing, 1944
Buku Teks SO
Snow, Edgar
Random House, 1941
Buku Teks SO
Bisson, T.A.
Macmillan, 1945
Buku Teks SO
Hubbard, G.E.
International Secretariat Institute of Pasific Relations, 1943
Buku Teks
Bisson, T.A.
International Secretariat Institute of Pasific Realtions , 1945
Buku Teks