Paul F. Syverson Gene Tsudik Michael G. Reed Carl E. Landwehr Towards an Analysis of Onion Routing Security. 96-114 2000 conf/diau/2000 Workshop on Design Issues in Anonymity and Unobservability http://link.springer.de/link/service/series/0558/bibs/2009/20090096.htm db/conf/diau/diau2000.html#SyversonTRL00