I. A. Smirnov, O. A. Malafeyev, T. Yu. Yakovets. "THE PROBLEM OF CLUSTERING CITIES IN THE NORTH OF RUSSIA ON THE SOCIO-DEMOGRAPHIC DATA." 6th SWS International Scientific Conference on Social Sciences ISCSS 2019 (2019): 305-310. https://doi.org/10.5593/SWS.ISCSS.2019.5/S18.038