ZavizionG. V. and ShkiIN. I. (1999) “Systems of singularly perturbed degenerate integro-differential equations”, Ukrains’kyi Matematychnyi Zhurnal, 51(12), pp. 1694–1703. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/4772 (Accessed: 27July2024).