Encyclopedia of educational research; Volume 2
editor-in-chief, Harold E. Mitzel
Free Press, 1993
 Buku Referensi
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 : fifth edition, volume 4
Harold E. Mitzel, editor-in-chief
Free Press, 1993
 Buku Referensi
Encyclopedia of educational research; Volume 3
editor-in-chief, Marvin C. Alkin
MacMillan Library Reference USA, 1992
 Buku Referensi