@TechReport{stone+:singletons-tr,
  author = 	 {Chris Stone and Robert Harper},
  title = 	 {Deciding Type Equivalence for a Language with Singleton Kinds},
  institution =  {Carnegie Mellon University Computer Science Department},
  year = 	 1999,
  number =	 {CMU--CS--99--155},
  address =	 {Pittsburgh, PA},
  month =	 {August}
}