On an extension of a theorem of O. Szàsz
Compositio Mathematica, Tome 17 (1965-1966), pp. 281-285. 
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     title = {On an extension of a theorem of {O.} {Sz\`asz}},
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     year = {1965-1966},
     mrnumber = {204975},
     zbl = {0163.07803},
     language = {en},
     url = {http://archive.numdam.org/item/CM_1965-1966__17__281_0/}
}
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Hsiang, Fu Cheng. On an extension of a theorem of O. Szàsz. Compositio Mathematica, Tome 17 (1965-1966), pp. 281-285. http://archive.numdam.org/item/CM_1965-1966__17__281_0/

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O. Szàsz, [3] The jump of a function and its Fourier coefficients, Duke Math. Journ., 4 (1938), 401-407. | JFM | MR | Zbl

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