Foer, Joshua, author
Penguin Books, 2011
Buku Teks
Fakultas Psikologi Universitas Indonesia, 1996
UI - Skripsi (Membership)
Scott, Gini Graham, author
American Management Association, 2007
eBooks
DePorter, Bobbi, author
Kaifa, 2015
Buku Teks
Buzan, Tony, author
Penguin Books, 1991
Buku Teks