1. N. M. Krylov, “On Generalization of Rietz’s Least Squares Method for Numerical Integration of Equations in Mathematical Physics,” Tr. Fiz.-Mat. Viddilu Akad. Nauk USSR 3, 3–28 (1926).
2. V. I. Romanovskii, “On an Integro-Differential Equation,” Tr. SAGU, Ser. Mat., No. 12, 25–32 (1934).
3. A. I. Nekrasov, “On a Class of Linear Integro-Differential Equations,” Tr. Tsentr. Aerogidrodin. Inst., No. 190, 1–25 (1934).
4. Ya. V. Bykov, On Some Problems in the Theory of Integro-Differential Equations (Kirgiz. Gos. Univ., Frunze, 1957) [in Russian].
5. T. I. Vigranenko, “A Boundary Value Problem for Linear Integro-Differential Equations,” Zap. Leningr. Gorn. Inst. 33(3), 177–187 (1956).