@article{SM_1978_34_2_a7,
     author = {V. E. Slyusarchuk},
     title = {Estimates of the spectra and the invertibility of functional operators},
     journal = {Sbornik. Mathematics},
     pages = {243--258},
     publisher = {mathdoc},
     volume = {34},
     number = {2},
     year = {1978},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1978_34_2_a7/}
}