@article{10_4064__27_2_481_497,
     author = {Winfried Sickel},
     title = {Superposition of functions in {Sobolev} spaces of fractional order. {A} survey},
     journal = {Banach Center Publications},
     pages = {481--497},
     publisher = {mathdoc},
     volume = {27},
     number = {2},
     year = {1992},
     doi = {10.4064/-27-2-481-497},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/-27-2-481-497/}
}