1. The Theory of Approximation;Jackson,1930
2. Monotone approximation;Shisha;Pacific J. Math.,1965
3. Two theorems on the approximation of functions by algebraic polynomials;Teljakovskiĭ;Mat. Sb.,1966
4. Two theorems on the approximation of functions by algebraic polynomials
5. Approximation of functions by polynomials with integer coefficients;Trigub;Izv. Akad. Nauk SSSR Ser. Mat.,1962