@Article{GM-Hla-jmp98,
  author	= {G. Matz and F. Hlawatsch},
  title		= {Time-frequency transfer function calculus (symbolic calculus) of linear time-varying systems (linear operators) based on a generalized underspread theory},
  journal	= {J. Math. Phys., {S}pecial {I}ssue on {W}avelet and {T}ime-{F}requency {A}nalysis},
  year		= {1998},
  month		= {Aug.},
  volume	= {39},
  number	= {8},
  pages		= {4041--4071}
}