Andrews, Edmund, author
Chicago Academy of Sciences, 1944
Buku Referensi
Encyclopaedia Britannica, 1981
Buku Referensi
Encyclopaedia Britannica, 1981
Buku Referensi
Encyclopaedia Britannica, 1981
Buku Referensi
Bussmann, Hadumod, author
Routledge, 1996
Buku Referensi