@TechReport{dreyer+:ttrecmod,
  author = 	 {Derek R. Dreyer and Robert Harper and Karl Crary},
  title = 	 {Towards a Practical Type Theory for Recursive Modules},
  institution =  {Carnegie Mellon University School of Computer Science},
  year = 	 2001,
  number =	 {CMU--CS--01--112},
  address =	 {Pittsburgh, PA},
  month =	 {March}
}