Mulyava, O.M., and M.M. Sheremeta. “Belonging to Convergence Classes of Hadamard Compositions of Gelfond-Leont’ev Derivatives for Analytic Functions”. Carpathian Mathematical Publications, vol. 4, no. 1, June 2012, pp. 111-5, https://journals.pnu.edu.ua/index.php/cmp/article/view/2471.