D. Kubanek, T. Freeborn, J. Koton, and N. Herencsar, “Evaluation of (1 + α) Fractional-Order Approximated Butterworth High-Pass and Band-Pass Filter Transfer Functions”, ELEKTRON ELEKTROTECH, vol. 24, no. 2, pp. 37–41, Apr. 2018, doi: 10.5755/j01.eie.24.2.20634.