1. Best approximation and differential properties of two conjugate functions;Bari;Tr. Moskovsk. Mat. Obsc.,1956
2. Constructive Approximation;DeVore,1993
3. On convergence conditions for Dirichlet series on closed polygons;Dzjadyk;Sb. Math.,1974
4. On the relation between Fourier and Leont’ev coefficients with respect to the space AC(D¯);Forster;CMFT,2001
5. Exponential Series;Leont’ev,1976