1. Simonenko, I. B.: The Riemann boundary value problem for n pairs of functions with measurable coefficients and its application to the investigation of singular integrals in the spaces LP with weight. Izv. Akad. Nauk SSSR, Ser. Mat., 28: 2, 277–306 (1964) (Russian).
2. Simonenko, I. B.: Some general questions of the theory of the Riemann boundary value problem. Izv. Akad. Nauk SSSR, Ser. Mat., 32: 5, 1138-1146 (1968) (Russian)
3. also in: Math. USSR Izv. 2, 1091-1099 (1968).
4. Gohberg, I., and N. Ya. Krupnik: Introduction to the theory of one-dimensional singular integral operators. Shtiintsa, Kishinev 1973 (Russian); German transi.: Birkhäuser Verlag, Basel 1979.
5. Krupnik, N. Ya.: Some general questions of the theory of one-dimensional singular operators with matrix coefficients. In: Nesamosopryazh. Oper. (Mat. Issled., Vyp. 42), 91–112, Shtiintsa, Kishinev 1976 (Russian).