Slawomir Koziel Stanislaw Szczepanski Rolf Schaumann A general approach to continuous-time G<sub>m</sub>-C filters based on matrix descriptions. 647-650 2002 ISCAS (4) http://doi.ieeecomputersociety.org/10.1109/ISCAS.2002.1010539 db/conf/iscas/iscas2002-4.html#KozielSS02a