Hewes ,Rachel
Rockport Publishers, 2010
Buku Referensi
Rizki Aulia Syahrizal
2016
UI - Skripsi (Membership)
Azka Amalia
2018
UI - Skripsi (Membership)
Abelson, Harold
Byte/McGraw-Hill, c1982
Buku Teks
Fakultas Psikologi Universitas Indonesia, 1993
UI - Skripsi (Membership)