Chaum, David. «Blind signatures for untraceable payments». Department of Computer Science, University of California, Santa Barbara, CA, 1982. Arxivat de l'original el 2011-09-03. [Consulta: 23 desembre 2017].
Chaum, David. «Blind signatures for untraceable payments». Department of Computer Science, University of California, Santa Barbara, CA, 1982. Arxivat de l'original el 2011-09-03. [Consulta: 23 desembre 2017].