Kim, Gang-Sok, Gwang-Ik Kim, Gwang-Nam Rim, and Sun-Nam Jang. “Methods for Comprehensive Analysis of the Economic Effectiveness of Business Activities: Special Reference to R & D Expenditure”. Business Perspective Review 3, no. 1 (January 12, 2021): 1–14. Accessed May 8, 2024. https://riiopenjournals.com/index.php/business-perspective-review/article/view/224.