Grolier Incorporated, 1991
Buku Referensi
Grolier, 1994
Buku Referensi
Warren Thomas Reich, editor in chief
Simon & Schuster Macmillan, 1995
Buku Referensi
edited by Edgar F. Borgatta, Marie L. Borgatta
Macmillan, 1992
Buku Referensi
edited by Alan Bryman
Sage, 2001
Buku Referensi