1. Atkinson D.(2014).Rural‐urban linkages: South Africa case study(Development with Territorial Cohesion Working Paper Series No. 125). Santiago Chile: Rimisp. Retrieved fromhttps://www.rimisp.org/wp-content/files_mf/1422297966R_ULinkages_SouthAfrica_countrycasestudy_Final_edited.pdf.
2. Branan N.(2010).Are our brains wired for categorization? Scientific America. Retrieved fromhttps://www.scientificamerican.com/article/wired-for-categorization.