Encyclopedia of educational research : sixth edition, volume 4
Marvin C. Alkin, editor-in-chief
MacMillan Library Reference USA, 1992
 Buku Referensi
Encyclopedia of educational research : sixth edition, volume 1
Marvin C. Alkin, editor-in-chief
MacMillan Library Reference USA, 1992
 Buku Referensi
Encyclopedia of educational research : sixth edition, volume 2
Marvin C. Alkin, editor-in-chief
MacMillan Library Reference USA, 1992
 Buku Referensi
Encyclopedia of knowledge : volume 4
Grolier Incorporated, 1991
 Buku Referensi
The Encyclopedia Americana : volume 4
Grolier, 1994
 Buku Referensi