@article{AFM_2015_40_1_a12,
     author = {Alessio Fiscella and Raffaella Servadei and Enrico Valdinoci},
     title = {Density properties for fractional {Sobolev} spaces},
     journal = {Annales Fennici Mathematici},
     pages = {235--253},
     publisher = {mathdoc},
     volume = {40},
     number = {1},
     year = {2015},
     doi = {10.5186/aasfm.2015.40xx},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.5186/aasfm.2015.40xx/}
}