Amelia, E., Okte, M., Hasanah, A. and Pratiwi, V. 2025. Building Competitive Advantage and Business Success through Self-Efficacy, Product Diversity, and Promotion Strategy. Business Innovation and Entrepreneurship Journal. 7, 3 (Aug. 2025), 204-210. DOI:https://doi.org/10.35899/biej.v7i3.1039.