Password Exhaustion: Predicting the End of Password Usefulness. - Luke St. Clair; Lisa Johansen; William Enck; Matthew Pirretti; Patrick Traynor; Patrick D. McDaniel; Trent Jaeger (ICISS, 2006)

Email Communities of Interest. - Lisa Johansen; Michael Rowell; Kevin R. B. Butler; Patrick D. McDaniel (CEAS, 2007)