Pachpatte, S. B., and B. G. Pachpatte. “Inequalities for Terminal Value Problems for Differential Equations”. Tamkang Journal of Mathematics 33, no. 3 (September 30, 2002): 199–208. Accessed April 20, 2024. https://journals.math.tku.edu.tw/index.php/TKJM/article/view/322.