KUMAR, S.; YADAV, A. Chain ratio and product estimators for population mode using two-phase sampling scheme. International Journal of Scientific Reports, [S. l.], v. 9, n. 10, p. 314–325, 2023. DOI: 10.18203/issn.2454-2156.IntJSciRep20232910. Disponível em: https://www.sci-rep.com/index.php/scirep/article/view/1255. Acesso em: 26 sep. 2025.