@workingPaper{BergerFehrleKlöcknerSchöllesThiesWahlster_1993,
title={PLUS : plan-based user support final project report},
author={Berger, Frank and Fehrle, Thomas and Klöckner, Kristof and Schölles, Volker and Thies, Markus A. and Wahlster, Wolfgang},
doi={http://dx.doi.org/10.22028/D291-24872},
year={1993}
}