Johnson, Elmer D., author
The Scarecrow Press, 1970
Buku Teks
editor in chief, Mortimer J. Adler
Encyclopedia Britanica, 1990
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
Adler, Mortimer J., 1902-2001 (change)
Chicago, Encyclopedia Britanica, Inc, 1990,
Buku Referensi