Kovács, Sándor, and Péter Balogh. “Clusteranalysis As a Swine Farm Qualifying Method”. Acta Agraria Debreceniensis0, no. 27 (November 15, 2007): 165-174. Accessed November 24, 2020. https://ojs.lib.unideb.hu/actaagrar/article/view/3121.