%0 Journal Article %A S. M. Tashpulatov %T Spectrum of the~energy operator of a~two-magnon system in the~three-dimensional isotropic Heisenberg ferromagnet model with impurity %J Teoretičeskaâ i matematičeskaâ fizika %D 2010 %P 227-242 %V 162 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/TMF_2010_162_2_a4/ %G ru %F TMF_2010_162_2_a4