Free, Michael L
New York, 1999
Buku Teks
Angelina Sulistio,author
Universitas Indonesia, 2006
UI - Tesis (Membership)
Maha Decha Dwi Putri
Fakultas Psikologi Universitas Indonesia, 2012
UI - Tesis (Open)
Westbrook, David
SAGE, 2007
Buku Teks
Arlita Permanasari
Fakultas Psikologi Universitas Indonesia, 2013
UI - Tesis (Membership)