@article{MAN_1977__230_163029,
     author = {Wolfgang Dahmen},
     title = {Trigonometrie {Approximation} with {Exponential} {Error} {Orders.} {I.} {Construction} of {Asymptotically} {Optimal} {Processes;} {Generalized} de la {Vall\'ee} {Poussin} {Sums.}},
     journal = {Mathematische Annalen},
     pages = {57--74},
     publisher = {mathdoc},
     volume = {230},
     year = {1977},
     zbl = {0342.42002},
     url = {http://geodesic.mathdoc.fr/item/MAN_1977__230_163029/}
}