DISCO---An HPSG-based NLP System and its Application for Appointment   Scheduling (Project Note)
  The natural language system DISCO is described. It combines o a powerful and flexible grammar development system; o linguistic competence for German including morphology, syntax and semantics; o new methods for linguistic performance modelling on the basis of high-level competence grammars; o new methods for modelling multi-agent dialogue competence; o an interesting sample application for appointment scheduling and calendar management. 
Hans Uszkoreit, Rolf Backofen, Stephan Busemann, Abdel Kader Diagne,   Elizabeth A. Hinkelman, Walter Kasper, Bernd Kiefer, ...