@Article{HlawatschBoelcskei96a,
  author	= {F. Hlawatsch and H. B{\"o}lcskei},
  title		= {Covariant time-frequency distributions based on conjugate operators},
  journal	= {IEEE Signal Processing Letters},
  year		= {1996},
  month		= {Feb.},
  volume	= {3},
  number	= {2},
  pages		= {44--46}
}