Brovenko, A. V., P. N. Melezhik, and PoedinchukA. К. “A Method for the Regularization of One Class of Dual Series Equations”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 53, no. 10, Oct. 2001, pp. 1320-7, https://umj.imath.kiev.ua/index.php/umj/article/view/4351.