1. Boundary value problems for the equation εy′ = f(x, y, y′) for small ϵ;Brish;Dokl. Akad. Nauk SSSR,1954
2. The asymptotics of the solution of certain problems for ordinary non-linear differential equations with a small parameter for the higher derivatives;Vasil'eva;Usp. mat. Nauk,1963
3. The initial jump for non-linear differential equations containing a small parameter;Vishik;Dokl. Akad. Nauk SSSR,1960
4. The asymptotic behaviour of solutions of a set of differential equations with a small parameter for the higher derivatives;Pontryagin;Akad. Nauk SSSR, Ser. Mat.,1957
5. Ordinary differential equations;Pontryagin,1961