@article{ASNSP_1975_4_2_3_479_0,
     author = {Kaufman, Robert},
     title = {Approximation of smooth functions and covering properties of sets},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     pages = {479--481},
     publisher = {Scuola normale superiore},
     volume = {Ser. 4, 2},
     number = {3},
     year = {1975},
     mrnumber = {379775},
     zbl = {0325.41018},
     language = {en},
     url = {http://www.numdam.org/item/ASNSP_1975_4_2_3_479_0/}
}