Lykins, Lorrie
American Society for Training & Development, 2011
eBooks
Rosling, Hans
Gramedia Pustaka Utama , 2019
Buku Teks
Gutsche, Jeremy, 1978-
Crown Business, 2015
Buku Teks
Moore, Raymond S
Reader's Digest Press, 1975
Buku Teks
Russell, Louise B.
The Brookings Institution, 1986
Buku Teks