Ybyrajhan, M.Y., and K.S. Uskembaev. “The Situation of Workers of the Central Kazakhstan Mining and Metallurgical Industry Late Nineteenth and Early Twentieth Centuries”. Bulletin of the Karaganda University History. Philosophy Series, vol. 86, no. 2, June 2017, pp. 81-89, https://ejh.buketov.edu.kz/history-philosophy-vestnik/article/view/217.