@article{RM_2016_71_5_a1,
     author = {A. A. Shkalikov},
     title = {Perturbations of self-adjoint and normal operators with discrete spectrum},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {907--964},
     publisher = {mathdoc},
     volume = {71},
     number = {5},
     year = {2016},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_2016_71_5_a1/}
}