Archer, John
Cambridge University Press, 2002
Buku Teks SO
Lips, Hilary M.
McGraw-Hill, 2008
Buku Teks
editors, Mary Laing, Katy Pilcher and Nicola Smith
Routledge, 2015
Buku Teks
Prabowo Bayu Waskito
Fakultas Psikologi Universitas Indonesia, 1986
UI - Skripsi Membership
Lianny Hendrata
Pohon Cahaya, 2011
Buku Teks SO