Bruce Schneier (2003) Beyond fear. New York: Copernicus Books.
Cranor, L.F. and Garfinkel, S. (2005) Security and usability: designing secure systems that people can use. Sebastopol, Calif: O’Reilly. Available at: http://www.vlebooks.com/vleweb/product/openreader?id=UCL&isbn=9780596514891.