1. M.A. Soderstrand, S.K. Mitra, Extremely low sensitivity active RC filters. Proc. IEEE 57(12), 2175 (1969)
2. P.R. Geffe, A Q-invariant active resonator. Proc. IEEE 57(8), 1442 (1969)
3. T. Deliyannis, A low-pass filter with extremely low sensitivity. Proc. IEEE 58(9), 1366–1367 (1970)
4. R.P. Sallen, E.L. Key, A practical method of designing RC active filters. Trans. IRE. CT 2(1), 74–85 (1955)
5. A.S. Sedra, A class of stable active filters using unity gain voltage followers. IEEE J. SC 7(4), 311–315 (1972)