A SECURE E - COUPON SERVICE BASED ON BLOCK CHAIN SYSTEM . Phoenix: International Multidisciplinary Research Journal ( Peer reviewed High Impact Journal ), [S. l.], v. 1, n. 3, p. 63–67, 2023. DOI: 10.5281/53wktd47. Disponível em: https://pimrj.org/index.php/pimrj/article/view/79.. Acesso em: 10 aug. 2025.