On the absolute summability factors of Fourier series at a given point
Compositio Mathematica, Tome 17 (1965-1966) , pp. 156-160. 
@article{CM_1965-1966__17__156_0,
     author = {Hsiang, Fu Cheng},
     title = {On the absolute summability factors of Fourier series at a given point},
     journal = {Compositio Mathematica},
     pages = {156--160},
     publisher = {Kraus Reprint},
     volume = {17},
     year = {1965-1966},
     zbl = {0178.06501},
     mrnumber = {208268},
     language = {en},
     url = {archive.numdam.org/item/CM_1965-1966__17__156_0/}
}
Hsiang, Fu Cheng. On the absolute summability factors of Fourier series at a given point. Compositio Mathematica, Tome 17 (1965-1966) , pp. 156-160. http://archive.numdam.org/item/CM_1965-1966__17__156_0/

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