Seongmi Kang, Shinjo Eom, Sangchul Kim. “Preliminary Study on Project Deliverable, an Innovation Activity for Customer Life Time Value”. Mathematical Statistician and Engineering Applications 71, no. 3 (June 9, 2022): 497 –. Accessed April 28, 2024. https://www.philstat.org/index.php/MSEA/article/view/188.