@article{10_4153_CJM_2010_040_1,
     author = {Ditzian, Z. and Prymak, A.},
     title = {Approximation by {Dilated} {Averages} and {K-Functionals}},
     journal = {Canadian journal of mathematics},
     pages = {737--757},
     year = {2010},
     volume = {62},
     number = {4},
     doi = {10.4153/CJM-2010-040-1},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-2010-040-1/}
}