Mussagaliyeva, A.S., and R.M. Mussabekova. “Special Contingent in the Development of Virgin and Fallow Lands of Northern Kazakhstan ”. Bulletin of the Karaganda University History. Philosophy Series, vol. 91, no. 3, Sept. 2018, pp. 63-72, https://ejh.buketov.edu.kz/history-philosophy-vestnik/article/view/354.