Mikhailets, V.A., and T.B. Skorobohach. “Fredholm Boundary- Value Problems With Parameter in Sobolev— Slobodetsky Spaces”. Reports of the National Academy of Sciences of Ukraine, no. 4 (August 26, 2021): 3–8. Accessed March 22, 2025. https://nasu-periodicals.org.ua/index.php/dp/article/view/2021-4-1.