MOYASSER AHMED, dr.; ISMAEEL, O. Statistical Concept of Six Sigma & Its Relationship With Processes Improvement Functions. TANMIYAT AL-RAFIDAIN, [S. l.], v. 31, n. 93, p. 124–143, 2009. DOI: 10.33899/tanra.2009.161832. Disponível em: https://edusj.uomosul.edu.iq/index.php/tanmiyat/article/view/29593. Acesso em: 10 sep. 2025.