@article{BUMI_1949_3_4_1_a6,
     author = {Sbrana, Francesco},
     title = {Sugli operatori funzionali multipli},
     journal = {Bollettino della Unione matematica italiana},
     pages = {34--40},
     publisher = {mathdoc},
     volume = {Ser. 3, 4},
     number = {1},
     year = {1949},
     zbl = {0033.27402},
     mrnumber = {30031},
     language = {it},
     url = {http://geodesic.mathdoc.fr/item/BUMI_1949_3_4_1_a6/}
}