@article{INTO_2021_192_a1,
     author = {I. V. Astashova and D. A. Sokolov},
     title = {Periodic solutions of a fourth-order nonlinear spectral problem},
     journal = {Itogi nauki i tehniki. Sovremenna\^a matematika i e\"e prilo\v{z}eni\^a. Temati\v{c}eskie obzory},
     pages = {20--25},
     publisher = {mathdoc},
     volume = {192},
     year = {2021},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/INTO_2021_192_a1/}
}