Schulz, Esther D.
Harcourt Brece & World, 1969
Buku Teks
Fakultas Psikologi Universitas Indonesia, 1993
UI - Skripsi (Membership)
Sumarno [and others]
BPNB, 2013
Buku Teks
Helaine Selin
Springer Science, 2012
eBooks
Gayle, Mike, author
Seeing other people, 2015
Buku Teks