Keene, Donald, author
Grove Press, 1955
Buku Teks
Keene, Donald, author
J. Murray, 1953
Buku Klasik
editor in cheief, Mortimer J. Adler
Encyclopedia Britanica, 1996
Buku Referensi
Adler, Mortimer J., 1902-2001 (change)
Chicago, Encyclopedia Britanica, Inc, 1990,
Buku Referensi
Chicago, Encyclopedia Britanica, Inc,, 1996
Buku Referensi