1. Topology;Dugundji,1966
2. Jackson type theorems for approximation with side conditions;Johnson;J. Approximation Theory,1974
3. On the Weierstrass approximation theorem;Paszkowski,1956
4. On approximation with nodes;Paszkowski;Rozpr. Mat.,1957
5. On an extension of Hellys theorem;Yamabe;Osaka J. Math.,1950