Romanov, A., O. Kondakova, A. Sulimov, V. Sulimov, and D. Vtyurina. “Calculation of Excited States of the Polycation Bi 3+ 5 by the Spin-Orbit Configuration Interaction Method”. Numerical Methods and Programming (Vychislitel’nye Metody I Programmirovanie), vol. 12, no. 30, Nov. 2011, pp. 443-9, https://en.num-meth.ru/index.php/journal/article/view/480.