Hall, J. Oliver
Problem solving in our America democracy
America Book Company, 1958
 Buku Teks SO
Bossing, Nelson L.
Solving our problems in a democracy
Laidlaw Brothers, 1956
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Myrdal, Gunnar, 1898-
An American dilemma: the Negro problem and modern democracy
Harper & Brothers , 1944
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Robertson, S. Ian
Problem solving
Psychology Press, 2001
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Patterson, Thomas E.
The American democracy
McGraw-Hill, 203
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