Naenudorn, Khanithar, and Charinthip Hengkrawit. “A Remark on a Functional Equation Related to Digital Filtering”. Thai Journal of Science and Technology 2, no. 3 (November 14, 2013): 226–230. Accessed March 29, 2024. https://li01.tci-thaijo.org/index.php/tjst/article/view/14461.