Dragomir, S. S., and N. S. Barnett. “An Ostrowski Type Inequality for Mappings Whose Second Derivatives Are Bounded and Applications”. The Journal of the Indian Mathematical Society 66, no. 1-4 (December 1, 1999): 237–245. Accessed May 7, 2024. https://www.informaticsjournals.com/index.php/jims/article/view/22008.