Newport, Cal, author
Noura Books, 2016
Buku Teks
Belsky, Scott, author
Noura Books, 2016
Buku Teks
Scott, Gini Graham, author
American Management Association, 2009
eBooks
Maxwell, John C., author
MIC, 2020
Buku Teks
Tam, Marilyn, author
Gramedia Pustaka Utama, 2007
Buku Teks