Johnson, Spencer, author
Harper Collins, 2004
Buku Teks
Webber, Ross A., author
Richard D. Irwin, 1981
Buku Teks
Fakultas Psikologi Universitas Indonesia, 2004
UI - Tesis (Membership)
Amanda Askew
Miles Kelly, 2011
Buku Teks
Kent, Peter, author
Prentice Hall of India, 1996
Buku Teks