AgarwalP., JabeenT., LupulescuV., and O’ReganD. “Existence of Global Solutions for Some classes of Integral Equations”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 70, no. 1, Jan. 2018, pp. 130-48, http://umj.imath.kiev.ua/index.php/umj/article/view/1546.