@article{PA_2017_6_2_a0,
     author = {G. G. Akniyev},
     title = {Discrete least squares approximation of piecewise-linear functions by trigonometric polynomials},
     journal = {Problemy analiza},
     pages = {3--24},
     publisher = {mathdoc},
     volume = {6},
     number = {2},
     year = {2017},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PA_2017_6_2_a0/}
}