1. N.I. Achieser, Vorlesungen über Approximationstheorie. Akademie Verlag, Berlin, 1953.
2. S.N. Bernstein, “Sur la meilleure approximation de |x| par les polynomes de degrés donnés”. Acta M. 37 (1914), 1–57.
3. H.P. Blatt and E.B. SafF, “Behavior of Zeros of Polynomials of Near Best Approximations”. Submitted to Math. Ztschr.
4. R. Grothmann and E.B. Saff, “On the behavior of zeros and poles of best uniform polynomial and rational approximants”, to appear.