Klahan, K., W. Tangsrirat, W. Surakampontorn, and T. Dumawipata. “Current-Mode Integrator Using OA and OTAs and Its Applications”. Science & Technology Asia, vol. 8, no. 2, Nov. 2015, pp. 26-32, https://ph02.tci-thaijo.org/index.php/SciTechAsia/article/view/41728.