@article{10_1017_S0017089500009721,
     author = {Bouldin, Richard},
     title = {Approximating {Fredholm} operators on a nonseparable {Hilbert} space},
     journal = {Glasgow mathematical journal},
     pages = {167--178},
     year = {1993},
     volume = {35},
     number = {2},
     doi = {10.1017/S0017089500009721},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500009721/}
}