Makhanets, O. M., A. I. Kuchak, and V. I. Gutsul. “Spectral Parameters of Electron in a Multishell Semiconductor Cylindrical Nanotube With a Donor Impurity at Its Axis”. Ukrainian Journal of Physics, vol. 59, no. 8, Oct. 2018, p. 819, doi:10.15407/ujpe59.08.0819.