@book{RitzBenzStender2003,
  author    = {Ritz, Thomas and Benz, Axel and Stender, Michael},
  title     = {Marktstudie mobile CRM-Systeme},
  publisher = {Fraunhofer-IRB-Verl.},
  address   = {Stuttgart},
  isbn      = {3-8167-6361-8},
  pages     = {244 S. : Ill., graph. Darst.},
  year      = {2003},
  language  = {en}
}
@article{FerreinFritzLakemeyer2003,
  author    = {Ferrein, Alexander and Fritz, Christian and Lakemeyer, Gerhard},
  title     = {Extending DTGOLOG with Options / Ferrein, Alexander ; Fritz, Christian ; Lakemeyer, Gerhard},
  series = {IJCAI-03, Proceedings of the Eighteenth International Joint Conference on Artificial Intelligence, Acapulco, Mexico, August 9-15, 2003},
  journal   = {IJCAI-03, Proceedings of the Eighteenth International Joint Conference on Artificial Intelligence, Acapulco, Mexico, August 9-15, 2003},
  pages     = {1391 -- 1393},
  year      = {2003},
  language  = {en}
}