Sembiring, F., F. Zuska, B. Ginting, R. Ismail, and H. 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), Vol. 8, no. 4, July 2019, pp. 105-13, doi:10.20525/ijrbs.v8i4.282.