Konet, I. M., Perestyuk, N. A., Samoilenko, A. M., & Teplinsky, Y. V. (2002). International Scientific Conference on the Theory of Evolution Equations (Fifth Bogolyubov Readings). Ukrains’kyi Matematychnyi Zhurnal, 54(10), 1440. https://umj.imath.kiev.ua/index.php/umj/article/view/4182