Dobushovs’kyi, M. S., and M. M. Sheremeta. “Estimations of the Laplace – Stieltjes Integrals”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 68, no. 11, Nov. 2016, pp. 1467-82, https://umj.imath.kiev.ua/index.php/umj/article/view/1934.