@article{10_21136_MB_1999_126249,
     author = {Appell, J\"urgen and Conti, G. and Santucci, P.},
     title = {Alcune osservazioni sul rango numerico per operatori non lineari},
     journal = {Mathematica Bohemica},
     pages = {185--192},
     publisher = {mathdoc},
     volume = {124},
     number = {2-3},
     year = {1999},
     doi = {10.21136/MB.1999.126249},
     mrnumber = {1780691},
     zbl = {0940.47052},
     language = {it},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/MB.1999.126249/}
}