Barnett, N. S., and S. S. Dragomir. “Some Landau Type Inequalities for Functions Whose Derivatives Are of Locally Bounded Variation”. Tamkang Journal of Mathematics 37, no. 4 (December 31, 2006): 301–308. Accessed August 19, 2022. https://journals.math.tku.edu.tw/index.php/TKJM/article/view/144.