Hubbard, G. E., author
International Secretariat Institute of Pasific Relations , 1943
Buku Teks
Lowe, Peter
Martin's Press , 1969
Buku Teks
London : Pancy Lund Humpries
Majalah, Jurnal, Buletin
Bisson, T.A., author
Macmilan Co., 1945
Buku Teks
Griswold, Alfred Whitney, 1906-1963, author
Harcourt, Brace , 1938
Buku Teks