%0 Journal Article %A O. V. Kholostova %T On Periodic Motions of a Nonautonomous Hamiltonian System at Resonance 2:1:1 %J Russian journal of nonlinear dynamics %D 2024 %P 493-511 %V 20 %N 4 %I mathdoc %U http://geodesic.mathdoc.fr/item/ND_2024_20_4_a4/ %G en %F ND_2024_20_4_a4