@InCollection{DartZobel92,
  author = 	 {Philip W. Dart and Justin Zobel},
  title = 	 {A Regular Type Language for Logic Programs},
  booktitle = 	 {Types in Logic Programmin},
  pages =	 {31--69},
  publisher =	 {MIT Press},
  year =	 1992,
  editor =	 {Frank Pfenning},
  chapter =	 5
}