Dragomir SS. Improvements of Ostrowski and generalised trapezoid inequality in terms of the upper and lower bounds of the first derivative. Tamkang J. Math. [Internet]. 2003 Sep. 30 [cited 2024 Apr. 18];34(3):213-22. Available from: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/312