Locke, Lawrence F.
Sage, 1987
Buku Referensi
Jähne, Johannes
Edition Leipzic, 1964
Buku Teks
Thomas, Robert Murray, 1921-
Corwin Press, 2008
Buku Teks
Thomas, Robert Murray, 1921-
Bergin & Garvey, 2000
Buku Teks
Steve, Theobald
[American Society for Training & Development Press;, ], 2002
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