[1] J. Šmerk:
The Approximation of Functions in the Sense of Tchebychev I. Archivum Mathematicum, XI, 1975.
MR 0412696
[2] G. Meinardus: Aproximace funkcí. Prague 1968.
[3] R. E. Edwards:
Functional Analysis. Moscow 1969 (Russian).
Zbl 0189.12103
[4] J. Šmerk: Rovnoměrná aproximace funkcí. Thesis, Faculty of Science of JEP University, Brno 1972.