@TechReport{dreyer+03:saferec-tr,
  author = 	 {Derek Dreyer and Robert Harper and Karl Crary},
  title = 	 {A Type System for Safe Recursion},
  institution =  {Carnegie Mellon University Computer Science Department},
  year = 	 2003,
  number =	 {CMU--CS--03--163},
  address =	 {Pittsburgh, PA},
  month =	 {August}
}