Malof, David
Chatto & Windus, 1990
Buku Teks
editor in chief, Mortimer J. Adler
Encyclopedia Britanica, 1990
Buku Referensi
Preston, Antony
Chancellor Press , 1999
Buku Referensi
editor in cheief, Mortimer J. Adler
Encyclopedia Britanica, 1996
Buku Referensi
Adler, Mortimer J., 1902-2001 (change)
Chicago, Encyclopedia Britanica, Inc, 1990,
Buku Referensi