Pugh, D.S.
Penguin Books, 1971
Buku Teks
Mohamad Ridwan, author
Badan Litbang Kementerian Pekerjaan Umum dan Perumahan Rakyat, 2017
Artikel Jurnal
Lykins, Lorrie, author
American Society for Training & Development, 2011
eBooks
Bedeian, Arthur G.
Dryden Press, 1991
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Harrison, Michael I.
Sage publications, 1987
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