OKE, S. SIX SIGMA: A LITERATURE REVIEW. The South African Journal of Industrial Engineering, [S. l.], v. 18, n. 2, 2011. DOI: 10.7166/18-2-122. Disponível em: http://sajie.journals.ac.za/pub/article/view/122. Acesso em: 11 apr. 2025.