Stepanov, I., O. Efremov, N. Suvorov, M. Danilovsky, N. Maydanov, and S. Schklyaruk. “Informative Core of the Mathematical Model of the Learning Curve”. Information and Control Systems, no. 1, Feb. 2011, pp. 34–40, https://i-us.ru/index.php/ius/article/view/13823.