Using the Six Sigma methodology as an internal control system to improve the quality of the internal audit process: An analytical study of a sample opinions of the General Company for Fertilizers Industry - Southern Region employees. Entrepreneurship Journal for Finance and Business, [S. l.], v. 7, n. 1, p. 89–101, 2026. DOI: 10.56967/ejfb2026630. Disponível em: https://ejfb.journalpath.com/ejfb/article/view/461. Acesso em: 21 jul. 2026.