Encyclopedia Britannica, 1983
Buku Referensi
Encyclopaedia Britannica, 2002
Buku Referensi
general editor, Sir Lawrence Gowing
Encyclopaedia Britannica, 2005
Buku Referensi
general editor, Sir Lawrence Gowing
Encyclopaedia Britannica, 2005
Buku Referensi
general editor, Sir Lawrence Gowing
Encyclopaedia Britannica, 2005
Buku Referensi