Storr, Anthony
Penguin, 1960
Buku Teks
Norris, Pippa
NY Cambridge University Press, 2014
Buku Teks
Pippa Norris, Richard W. Frank, and Ferran MartÃnez i Coma.
Oxford University Press , 2014
Buku Teks
edited by Alan Montefiore and David Vines
Routledge, 1999
Buku Teks
Fernandez, Eduardo B.
Addison-Wesley, 1981
Buku Teks