Armstrong, Michael, author
Crest Publishing House, 1999
Buku Teks
Dwi Waryaningsih, author
Fakultas Psikologi Universitas Indonesia, 2015
UI - Tesis (Membership)
Bond, Meg, author
McGraw-Hill, 2010
Buku Teks
Armstrong, Michael, author
[Publisher not identified], [Date of publication not identified]
Buku Teks
McIver, Colin
Longman , 1972
Buku Teks