Dragomir, S. S. “Integral Inequalities of the Hermite – Hadamard Type for $K$ -Bounded Norm Convex Mappings”. Ukrains’kyi Matematychnyi Zhurnal, vol. 68, no. 10, Oct. 2016, pp. 1330-47, https://umj.imath.kiev.ua/index.php/umj/article/view/1924.