Synthesis of electronically tunable multifunction biquad filter using voltage differencing differential input buffered amplifiers. - Bunrueangsak, Sirigul; Jaikla, Winai; Chaichana, Amornchai; Supavarasuwat, Piya; Siripongdee, Surapong; Suwanjan, Peerawut (ETRI Journal, 2025)