Srisuchinwong, B., and A. Leelasantitham. “A 2V CMOS Capacitorless Current-Tunable All-Pass Filter Using Current Mirrors”. Science & Technology Asia, vol. 6, no. 1, Nov. 2015, pp. 46-51, https://ph02.tci-thaijo.org/index.php/SciTechAsia/article/view/41882.