@article{PORMA_1985__43_1_114502,
     author = {Bebiano, Nat\'alia},
     title = {Some variations on the concept of the c-numerical range},
     journal = {Portugaliae mathematica},
     pages = {189--200},
     publisher = {mathdoc},
     volume = {43},
     number = {1},
     year = {1985},
     mrnumber = {0875067},
     zbl = {0613.15022},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1985__43_1_114502/}
}