Baranetskij, Ya.O., I.I. Demkiv, A.V. Solomko, and O.M. Sus’. “Nonlocal Multipoint Problem for a Differential Equation of $2n$-Th Order With Operator Coefficients”. Carpathian Mathematical Publications 13, no. 2 (October 29, 2021): 501–514. Accessed April 20, 2024. https://journals.pnu.edu.ua/index.php/cmp/article/view/4998.