Bless, Herbert, author
Psychology Press, 2004
Buku Teks
Martin, J. R., author
Oxford University Press , 1989
Buku Teks
Brekhus, Wayne.
MA Polity Press, 2015
Buku Teks
Simpson, Sally S.
Cambridge University Press, 2002
Buku Teks
edited by V.A.C. Gatrell, Bruce Lenman, and Geoffrey Parker
Europa Publications, 1980
Buku Referensi