%0 Journal Article %A S. Albeverio %A S. Fassari %A F. Rinaldi %T Spectral properties of a symmetric three-dimensional quantum dot with a pair of identical attractive $\delta$-impurities symmetrically situated around the origin %J Nanosistemy: fizika, himiâ, matematika %D 2016 %P 268-289 %V 7 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/NANO_2016_7_2_a0/ %G en %F NANO_2016_7_2_a0