%0 Journal Article %A S. M. Tashpulatov %T Structure of essential spectra and discrete spectrum of the energy operator of two-magnon systems with four-spin exchange Hamiltonian %J Taurida Journal of Computer Science Theory and Mathematics %D 2024 %P 75-85 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/TVIM_2024_2_a4/ %G ru %F TVIM_2024_2_a4