@book{DBLP:books/daglib/0070404,
  author = {Bibel, Wolfgang and H{\"{o}}lldobler, Steffen and Schaub, Torsten},
  title = {Wissensrepr{\"{a}}sentation und Inferenz - eine grundlegende Einf{\"{u}}hrung},
  series = {Artificial Intelligence},
  publisher = {Vieweg},
  year = {1993}
}