Gauwitz, Donna F, author
McGraw-Hill, Higher Education, 2005
Buku Teks
Bayt, Phyllis Theiss
Glencoe Publishing Company, 1982
Buku Teks
Humphries, Judith
Kogan Page, 1994
Buku Teks
Tulloch, Mitch, author
McGraw-Hill, 2000
Buku Referensi
Overfield, Karen, author
American Society for Training & Development, 1997
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