@article{10_4064_sm_1998_130_2_1_171_192,
     author = {W. D.  Evans and D. J. Harris and J. Lang},
     title = {Two-sided estimates for the approximation numbers of {Hardy-type} operators in $L^{\ensuremath{\infty}}$ and {L{\textonesuperior}}},
     journal = {Studia Mathematica},
     pages = {171--192},
     year = {1998},
     volume = {130},
     number = {2},
     doi = {10.4064/sm_1998_130_2_1_171_192},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm_1998_130_2_1_171_192/}
}