@Conference{TwarochHlawatsch98a,
  author	= {T. Twaroch and F. Hlawatsch},
  title		= {Modulation and warping operators in joint signal analysis},
  booktitle	= {Proc. IEEE-SP Int. Sympos. Time-Frequency Time-Scale Analysis},
  year		= {1998},
  month		= {Oct.},
  address	= {Pittsburgh, PA},
  pages		= {9--12}
}