Soewarno, L. E. S., W. J. A. Tumbuan, and A. H. Jan. “Effect of Promotional Mix on Credit Card Usage Decisions for Customers of PT BNI (Persero) Tbk Manado Area During the Covid-19 Pandemic”. International Journal on Economics, Finance and Sustainable Development, Vol. 4, no. 6, June 2022, pp. 92-101, https://journals.researchparks.org/index.php/IJEFSD/article/view/3205.