%0 Journal Article %A S. M. Tashpulatov %A R. T. Parmanova %T Structure of the essential spectrum and discrete spectrum of the energy operator of four-electron systems in the impurity Hubbard model. The third triplet state %J Itogi nauki i tehniki. Sovremennaâ matematika i eë priloženiâ. Tematičeskie obzory %D 2023 %P 53-82 %V 229 %I mathdoc %U http://geodesic.mathdoc.fr/item/INTO_2023_229_a6/ %G ru %F INTO_2023_229_a6