@article{RLIN_2003_9_14_3_a3,
     author = {Brezis, Ha{\"\i}m},
     title = {The fascinating homotopy structure of {Sobolev} spaces},
     journal = {Atti della Accademia nazionale dei Lincei. Rendiconti Lincei. Matematica e applicazioni},
     pages = {207--217},
     publisher = {mathdoc},
     volume = {Ser. 9, 14},
     number = {3},
     year = {2003},
     zbl = {1225.46024},
     mrnumber = {1120602},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RLIN_2003_9_14_3_a3/}
}