@article{DAN_1960_130_2_a1,
     author = {M. I. Vishik and L. A. Lyusternik},
     title = {Perturbation of eigenvalues and eigenelements for some non-selfadjoined operators},
     journal = {Doklady Akademii Nauk},
     pages = {251--253},
     publisher = {mathdoc},
     volume = {130},
     number = {2},
     year = {1960},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1960_130_2_a1/}
}