Morant, G.M., author
Unesco, 1952
Buku Teks
edited by Denton E. Morrison and Ramon E. Henkel
Aldine, 1973
Buku Teks
Briggs, Lawrence Palmer
The American Philosophical Society, 1951
Buku Teks
CRC press, 2020
eBooks
Hunt, Elgin F., author
MacMillan, 1987
Buku Teks