Gaya APA
Bower, S, A., Bower, G, H. (1984).
Asserting Yourself A Practical Guide for Positive Change (Cet.16).
USA:
Addison Wesley.
Gaya MLA
Bower, Sharon, Anthony., Bower, Gordon, H..
"Asserting Yourself A Practical Guide for Positive Change".
Cet.16
USA:
Addison Wesley,
1984.
Buku PSI.