@TechReport{Pohl92,
  author =    "Klaus Pohl",
  title =     "The {T}hree {D}imensions of {R}equirements {E}ngineering",
  institution = "RWTH Aachen",
  year =      "1992",
  number =    "AIB-24-1992",
  url =       "http://aib.informatik.rwth-aachen.de/1992/1992-24.ps.gz",
}