@article{1028999304,
author = {Curtis, Philip C.},
title = {The degree of approximation by positive convolution operators.},
journal = {Michigan Math. J.},
volume = {12},
number = {1},
year = {1965},
pages = { 155-160},
language = {en},
url = {http://dml.mathdoc.fr/item/1028999304}
}
Curtis, Philip C. The degree of approximation by positive convolution operators.. Michigan Math. J., Tome 12 (1965) no. 1, pp. 155-160. http://gdmltest.u-ga.fr/item/1028999304/