@Article{aeu-detect99,
  author	= {G. Matz and F. Hlawatsch},
  title		= {Time-frequency subspace detectors and application to knock detection},
  journal	= {Int. J. Electron. Commun. (AE\"U)},
  year		= {1999},
  volume	= {53},
  number	= {6},
  pages		= {379--385}
}