et. al., In-Wook Kim,. “An Empirical Study on the External Environment, Brand Expansion Strategy, and Core Competence of Business”. Turkish Journal of Computer and Mathematics Education (TURCOMAT) 12, no. 10 (April 28, 2021): 987–995. Accessed April 28, 2024. https://www.turcomat.org/index.php/turkbilmat/article/view/4283.