Kemm, John
Macmillan, 1995
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Simons-Morton, Bruce G.
Jones & Bartlett Learning, 2012
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Carl I. Fertman, Diane D. Allensworth
Jossey-Bass , 2017
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Pender, Nola J.
Appleton & Lange, 1987
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Naidoo, Jennie
Baillere Tindall , 2000
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