Soliman, A. M., and M. Fawzy,
"A universal active R biquad",
International Journal of Circuit Theory and Applications, vol. 6, no. 2: Wiley Online Library, pp. 153–157, 1978.
Abstract
Soliman, A. M., and S. A. Badre,
"A universal notch filter",
International Journal of Circuit Theory and Applications, vol. 7, no. 1: Wiley Subscription Services, Inc., A Wiley Company, pp. 139–142, 1979.
Abstract