1. Maehly, H., & C. Witzgall, Tschebyscheff-Approximationen in kleinen Intervallen. Numer. Math. 2, 142?150 (1960).
2. Cheney, E. W., & H. L. Loeb, Generalized rational approximation. SIAM J., Ser. B 1, 11?25 (1964).
3. Werner, H., On the rational Tschebysheff-operator. Math. Zeit. 86, 317?326 (1964). Principal results announced in Bull. Am. Math. Soc. 70, 554?555 (1964).
4. Cheney, E. W., Approximation by generalized rational functions, pp. 101?110 in [7]. Principal results announced in Notices. Amer. Math. Soc. 11, 461 (1964).
5. Loeb, H. L., Contributions to rational approximation, thesis, UCLA, 1965. Principal results announced in Notices. Amer. Math. Soc. 11, 335, 462, 689, 769 (1964).