Bibtex Entry:

@inproceedings{walfish2006distributed,
   author =       "Michael Walfish and J.D. Zamfirescu and Hari Balakrishnan and David Karger and Scott Shenker",
   title =        "{Distributed Quota Enforcement for Spam Control}",
   booktitle =    {3rd USENIX Symposium on Networked Systems Design and Implementation (NSDI)},
   year =         {2006},
   month =        {May},
   address =      {San Jose, CA}
}