@article{SchaubThielscher1996,
  author    = {Schaub, Torsten H. and Thielscher, Michael},
  title     = {Skeptical query-answering in constrained default logic},
  isbn      = {3-540-61313-7},
  year      = {1996},
  language  = {en}
}
@article{ThielscherSchaub1995,
  author    = {Thielscher, Michael and Schaub, Torsten H.},
  title     = {Default reasoning by deductive planning},
  year      = {1995},
  language  = {en}
}