1. http://www.cbsnews.com/stories/2010/02/15/business/main6209772.shtml
2. http://www.bbc.co.uk/news/10569081
3. http://www.eurosmart.com/images/doc/Eurosmart-in-the-press/2006/cardtechnologytoday_dec2006.pdf
4. http://www.gsaietsemiconductorforum.com/2010/delegate/documents/GASSELGSALondon20100518presented.pdf. (Slide 23)
5. Lecture Notes in Computer Science;T. Eisenbarth,2008