@article{PIM_1997_N_S_61_75_a9,
     author = {Sne\v{z}ana \v{Z}ivkovi\'c},
     title = {Semi-Fredholm {Operators} and {Perturbations}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {73 },
     publisher = {mathdoc},
     volume = {_N_S_61},
     number = {75},
     year = {1997},
     zbl = {0889.47003},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PIM_1997_N_S_61_75_a9/}
}