TY - JOUR AU - Dahmen, Wolfgang TI - Trigonometric approximation with exponential error orders. I. Construction of asymptotically optimal processes; generalized de la Vallée Poussin Sums JO - Mathematische Annalen VL - 230 SN - 0025-5831 CY - Berlin ; Göttingen ; Heidelberg PB - Springer M1 - RWTH-CONV-062020 SP - 57-74 PY - 1977 LB - PUB:(DE-HGF)16 UR - https://publications.rwth-aachen.de/record/185555 ER -