Baranetskij, Ya.O., P.I. Kalenyuk, M. I. Kopach, and A.V. Solomko. “The Nonlocal Multipoint Problem With Dirichlet-Type Conditions for an Ordinary Differential Equation of Even Order With Involution”. Matematychni Studii 54, no. 1 (October 5, 2020): 64-78. Accessed December 9, 2021. http://matstud.org.ua/ojs/index.php/matstud/article/view/31.