Flammini, Roxana. “Ancient Core-Periphery Interactions: Lower Nubia During Middle Kingdom Egypt (ca. 2050-1640 B.C.)”. Journal of World-Systems Research 14, no. 1 (February 26, 2008): 50–74. Accessed April 16, 2024. http://jwsr.pitt.edu/ojs/jwsr/article/view/348.