Lemma, Mulatu. “Matrix Based on the Second Derivative of Infinite Convergent Geometric Series”. Journal of Advance Research in Mathematics and Statistics (ISSN 2208-2409) 4, no. 3 (March 31, 2017): 01–05. Accessed December 22, 2024. https://nnpub.org/index.php/MS/article/view/543.