@article{TUW-103074,
author = {Matz, Gerald and Hlawatsch, Franz},
title = {Time-frequency transfer function calculus (symbolic calculus) of linear time-varying systems (linear operators) based on a generalized underspread theory},
journal = {Journal of Mathematical Physics},
year = {1998},
volume = {vol. 39},
number = {no. 8},
pages = {4041--4070},
url = {http://publik.tuwien.ac.at/files/pub-et_3308.pdf}
}