@TechReport{deyoung07:alwet,
  author =   {Henry DeYoung and Deepak Garg and Frank Pfenning},
  title =    {An Authorization Logic with Explicit Time},
  institution =  {Computer Science Department, Carnegie Mellon University},
  year =     2007,
  number =   {CMU-CS-07-166},
  month =    {December}
}