Askarov, M., and S. V. Pereverzev. “On the Rate of Convergence of Projection-Iterative Methods for Classes of Weakly Singular Integral Equations”. Ukrains’kyi Matematychnyi Zhurnal, vol. 47, no. 4, Apr. 1995, pp. 498–505, https://umj.imath.kiev.ua/index.php/umj/article/view/5447.