The encyclopedia of philosophy; volume 7 and 8
editor in chief, Paul Edwards
Macmilan , 1972
 Buku Referensi
The encyclopedia of philosophy volume 7 and 8
Paul Edwards, editor in chief
Macmilan , 1972
 Buku Referensi
The Encyclopedia Americana : the international reference work, volume 8
Americana Corporation, 1960
 Buku Referensi
The Encyclopedia Americana : the international reference work, volume 7
Americana Corporation, 1960
 Buku Referensi
International encyclopedia of islamic dynasties : (a continuing series) V ol. 8 Bangladesh
editor in chief, Nagendra Kr Singh
New Delhi : Anmol, 2000,
 Buku Referensi