Asimov, Isaac
Doubleday, 1964
Buku Referensi
Rengo Press, 1958
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