YANG, GOU-SHENG, and CHENG-DAR YOU. “A NOTE ON DISCRETE OPIAL’S INEQUALITY”. Tamkang Journal of Mathematics 23, no. 1 (March 1, 1992): 67–78. Accessed April 25, 2024. https://journals.math.tku.edu.tw/index.php/TKJM/article/view/4528.