The Encyclopedia of philosophy: volumes 3 and 4
editor, Paul Edwards
MacMilan, 1972
 Buku Referensi
International encyclopedia of linguistics; Volume 4
William Bright, editor-in-chief
Oxford University Press, 1992
 Buku Referensi
International encyclopedia of linguistics : volume 3
William Bright, editor-in-chief
Oxford University Press, 1992
 Buku Referensi
International encyclopedia of marketing; Vol. 3
edited by A.S. Bhamhra, A.K. Chaudhary
Anmol Publications PVT, 1998
 Buku Referensi
The Encyclopedia Americana : the international reference work, volume 4
Americana Corporation, 1960
 Buku Referensi