@article{DAN_1990_314_6_a9,
     author = {E. V. Radkevich},
     title = {The spectrum of the pencil of a two-phase {Stefan} problem},
     journal = {Doklady Akademii Nauk},
     pages = {1322--1327},
     publisher = {mathdoc},
     volume = {314},
     number = {6},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1990_314_6_a9/}
}