Selvam, K. C. “A Circuit for the Square Root of the Sum of Two Squared Voltages Using an IC LM311 Open Collector Comparator”. Engineering, Technology & Applied Science Research 3, no. 6 (December 18, 2013): 549–551. Accessed January 23, 2022. https://www.etasr.com/index.php/ETASR/article/view/241.