Nurfai, Nurfai Al Faizal. “The Effect of Promotion Cost and The Fixed Price on Sales Level of The PT. Aston Inti Makmur”. Mulia Pratama Jurnal Ekonomi dan Bisnis 1, no. 1 (August 3, 2023): 1-10. Accessed January 13, 2025. https://ejournal.stiemp.ac.id/mp/article/view/138.