1. Asymptotic values of best approximation of analytic functions in a complex domain;Al'per;Uspehi Mat. Nauk,1959
2. Nichtlineare Tschebysheff-Approximation;Brosowski,1968
3. A refinement of the Kolmogorov-Criterion;Brosowski,1981
4. Introduction to Approximation Theory;Cheney,1966
5. Complex Chebyshev polynomials on circular sections;Geiger;J. Approx. Theory,1978