@article{DAN_1977_234_4_a5,
     author = {N. Ya. Krupnik},
     title = {A quasi-nilpotency condition for integral operators. {Perturbation} of operators of local type},
     journal = {Doklady Akademii Nauk},
     pages = {754--757},
     publisher = {mathdoc},
     volume = {234},
     number = {4},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1977_234_4_a5/}
}