@TechReport{AlpuenteHanusLucasVidal99,
   author=      "Mar\'ia Alpuente and Michael Hanus and Salvador Lucas and Germ\'an Vidal",
   title=       "Specialization of {F}unctional {L}ogic {P}rograms {B}ased on {N}eeded {N}arrowing",
   institution= "RWTH Aachen",
   year=        "1999",
   number=      "AIB-04-1999",
   url=         "http://aib.informatik.rwth-aachen.de/1999/1999-04.ps.gz",
}