Pollack, Ervin H.
The Foundation Press, Inc, 1967
Buku Teks
Nedzel, Nadia E
Wolters Kluwer Law Business, 2008.
Buku Teks
Grossman, George S., author
Oxford University Press, 1994
Buku Teks
edited by Merlin C. Wittrock; a project of the American Educational Research Association
Macmillan Library Reference USA, 1986
Buku Referensi
Parker, Robert A., editor
Cambridge University Press, 2016
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