Andreas Pfitzmann Marit Köhntopp Anonymity, Unobservability, and Pseudonymity - A Proposal for Terminology. 1-9 2000 conf/diau/2000 Workshop on Design Issues in Anonymity and Unobservability http://link.springer.de/link/service/series/0558/bibs/2009/20090001.htm db/conf/diau/diau2000.html#PfitzmannK00