Roger Dingledine Michael J. Freedman David Hopwood David Molnar A Reputation System to Increase MIX-Net Reliability. 126-141 2001 conf/ih/2001 Information Hiding http://link.springer.de/link/service/series/0558/bibs/2137/21370126.htm db/conf/ih/ihw2001.html#DingledineFHM01