SENGUPTA, S.; CHUNG, D. W.; KUMAR, R.; GUPTA, P.; UPADHYAY, S.; RATTAN, A. Sigma metrics as quality indicators in guiding and tracking laboratory process improvement. International Journal of Research in Medical Sciences, [S. l.], v. 12, n. 1, p. 75–81, 2023. DOI: 10.18203/2320-6012.ijrms20233837. Disponível em: https://www.msjonline.org/index.php/ijrms/article/view/13028. Acesso em: 13 oct. 2025.