Neuchatel : de la Baconniere
Majalah, Jurnal, Buletin
editor in chief, Mortimer J. Adler
Encyclopedia Britanica, 1990
Buku Referensi
editor in chief, Mortimer J. Adler
Encyclopedia Britanica, 1990
Buku Referensi
Laidi, Zaki
London: Routledge, 1998,
Buku Teks
edited by Mortimer J. Adler
Encyclopedia Britanica, 1990
Buku Referensi