VasylykV. B., and MakarovV. L. “Exponentially Convergent Method for an Abstract Nonlocal Problem With Integral Nonlinearity”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 68, no. 12, Dec. 2016, pp. 1587-9, https://umj.imath.kiev.ua/index.php/umj/article/view/1945.