1. Identity Is the New Money;Birch,2014
2. Birch, D., Mcevoy, N., 1996. DIY Cash, Wired UK (April 1996).
3. Technology Will Denationalise Money;Birch,1997
4. The IBM Dollar;Bono,2002
5. Balancing accountability and privacy using e-cash;Camenisch,2006