1. M.T. Ashordia, On the continuous dependence on the parameter of the solution of the Cauchy problem for a system of generalized ordinary differential equations. (Russian)Proc. I. Vekua Inst. Appl. Math. Tbiliss. State Univ. 31(1988), 5–22.
2. M.T. Ashordia, On the stability of solutions of linear boundary value problems for a system of ordinary differential equations.Proc. Georgian Acad. Sci. Math. 1(1993), No. 2, 129–141.
3. I.T. Kiguradze, Boundary value problems for systems of ordinary differential equations. (Russian)Current problems in mathematics. Newest results, v. 30, (Russian) 3–103,Itogi nauki i tekhniki, Akad. Nauk SSSR, Vsesoyuzn. Inst. Nauchn i Tekhnich. Inform., Moscow, 1987.
4. M.A. Krasnoselski and S.G. Krein, Averaging principle in nonlinear mechanics. (Russian),Uspekhi Mat. Nauk 10(1955), No. 3, 147–152.
5. J. Kurzweil, Generalized ordinary differential equations and continuous dependence on a parameter.Czechoslovak Math. J. 7(1957), No. 3, 418–449.