1. Where Is Current Research on Blockchain Technology?—A Systematic Review
2. D. Tapscott and A. Tapscott Blockchain Revolution: How the Technology Behind Bitcoin Is Changing Money Business and the World. Portfolio ©2016 2016. D. Tapscott and A. Tapscott Blockchain Revolution: How the Technology Behind Bitcoin Is Changing Money Business and the World. Portfolio ©2016 2016.
3. How to time-stamp a digital document
4. Improving the Efficiency and Reliability of Digital Time-Stamping;Bayer D.;Seq. II (R. Capocelli, A. Santis, U. Vaccaro, eds.) Springer New York,1993
5. S. Nakamoto "Bitcoin: A Peer-to-Peer Electronic Cash System " p. 9 2008. S. Nakamoto "Bitcoin: A Peer-to-Peer Electronic Cash System " p. 9 2008.