@article{BUMI_1958_3_13_2_a0,
     author = {Speranza, Francesco},
     title = {Sulle corrispondenze polari.},
     journal = {Bollettino della Unione matematica italiana},
     pages = {157--159},
     publisher = {mathdoc},
     volume = {Ser. 3, 13},
     number = {2},
     year = {1958},
     zbl = {0082.36201},
     mrnumber = {98404},
     language = {it},
     url = {http://geodesic.mathdoc.fr/item/BUMI_1958_3_13_2_a0/}
}