@article{10_4064_sm149_2_5,
     author = {David Swanson},
     title = {Pointwise inequalities and approximation in
fractional {Sobolev} spaces},
     journal = {Studia Mathematica},
     pages = {147--174},
     year = {2002},
     volume = {149},
     number = {2},
     doi = {10.4064/sm149-2-5},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm149-2-5/}
}