@techreport{ahmed:verify,
   author    = {Tanvir Ahmed and Anand Tripathi},
   title     = {{Static Verification of Security Requirements in Role Based CSCW Systems}}
   institution = {Department of Computer Science, University of Minnesota},
   year      = {2002},
   month     = {Nov},
   note     = {Available at http://www.cs.umn.edu/Ajanta} 
}