Marianne Wait, editor
Reader's Digest, 2007
Buku Teks
Willmore, Job, author
American Society for Training & Development, 2009
eBooks
Inchauspe, Jessie, author
Simon & Schuste, 2022
Buku Teks
Davis, Jack, author
Currency, 1986
Buku Teks
Cohen, Suzy, author
Rodale, 2010
Buku Teks