@article{CMUC_1991__32_4_a6,
     author = {Gonzalez, Manuel and Martinon, Antonio},
     title = {Operational quantities derived from the norm and generalized {Fredholm} theory},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {645--657},
     publisher = {mathdoc},
     volume = {32},
     number = {4},
     year = {1991},
     mrnumber = {1159811},
     zbl = {0762.47005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1991__32_4_a6/}
}