DRAGOMIR, S. S. Improvements of Ostrowski and generalised trapezoid inequality in terms of the upper and lower bounds of the first derivative. Tamkang Journal of Mathematics, [S. l.], v. 34, n. 3, p. 213-222, 2003. DOI: 10.5556/j.tkjm.34.2003.312. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/312. Acesso em: 28 oct. 2021.