Sembiring, Feriel, Fikarwin Zuska, Bengkel Ginting, Rizabuana Ismail, and Henry Sitorus. “Ego-Centric Social Network Analysis in Marketing of Fish From Cage Culture System In Simalungun District, Indonesia”. International Journal of Research in Business and Social Science (2147- 4478) 8, no. 4 (July 3, 2019): 105-113. Accessed August 5, 2020. https://www.ssbfnet.com/ojs/index.php/ijrbs/article/view/282.