Knyazev С. Н., and Mikhailov Ю. О. “Method of Calculating the Technological Stress of Reduction for Tubular Part With Mandrel”. Intellekt. Sist. Proizv., vol. 13, no. 1, July 2015, pp. 46-47, https://izdat.istu.ru/index.php/ISM/article/view/1919.