et al., J. P. “EVALUATION ENERGY OF ELECTRONS IN CENTERS IN SI AND GE WITH VARIATIONAL MONTE CARLO METHOD. ANISOTROPY OF THE MASS”. International Journal of Advanced Science and Technology, Vol. 28, no. 15, Nov. 2019, pp. 525 -32, http://sersc.org/journals/index.php/IJAST/article/view/1807.