Myers, Robert G., author
Prepared for the Educational Research Review and Advisory Group, 1980
Buku Teks
Davis, Joel, 1950-, author
Prentice-Hall, 1997
Buku Teks
edited by Merlin C. Wittrock; a project of the American Educational Research Association
Macmillan Library Reference USA, 1986
Buku Referensi
Price, Miles O. (Miles Oscar), 1890-1968, author
Brown and Company, 1979
Buku Referensi
Parker, Robert A., editor
Cambridge University Press, 2016
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