Johnson, Spencer
Harper Collins, 2004
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Gamble, Teri Kwal
American Society for Training & Development, 2007
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Ardyan Yudha
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 2013
UI - Skripsi Membership
Lapp, Charles L.
McGraw-Hill, 1957
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Rodgers, Mark
McGraw-Hill , 2011
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