1. Alexander, C.K., Sadiku, M.N.O.: Fundamentals of Electric Circuits. McGraw-Hill (2006)
2. Zhu, L., Sun, S., Menze, W.: Ultra-Wideband bandpass filters using multiple-mode resonator. IEEE Microwave and Wireless Components Letters, 1–3 (2005)
3. Peng, F.Z.: Application issues of active power filter. IEEE Industry Application Magazine (1998)
4. Szentirmai, G.: Synthesis of multiple-feedback active filters. BSTJ, 527–555 (April 1974)
5. Fleischer, P.E., Tow, J.: Design formulas for biquad active filters using three operational amplifiers. Proc. IEEE 61(5), 662–663 (1973)