1. A fair non-repudiation protocol
2. ‘Relations amoung public key signature systems’, Technical Report 175, , Computer Science Department, Technicon, Haifa, Israel, 1980
3. ‘On the impossibility of fair exchange without a trusted third party’, Technical Report TUD-BS-1999-02, Darmstadt University of Technology, Department of Computer Science, Darmstadt, Germany, March, 1999 http://www.informatik.tu-darmstadt.de/BS/Gaertner/publications/TUD-BS-1999-02.ps.gz, accessed July 2009