Operational Performance Improvement Analysis Through Six Sigma Approach: Case Study at PT. Freight Express Surabaya. Jurnal Manajemen Bisnis, [S. l.], v. 13, n. 1, p. 718–729, 2026. DOI: 10.33096/jmb.v13i1.1455. Disponível em: http://jurnal.fe.umi.ac.id/index.php/JMB/article/view/1455. Acesso em: 3 apr. 2026.