SINGH, Housila P.; BIRADAR, R. S. A class of unbiased ratio estimators in two-phase sampling. Statistica, [S. l.], v. 54, n. 3, p. 349–359, 2013. DOI: 10.6092/issn.1973-2201/1021. Disponível em: https://rivista-statistica.unibo.it/article/view/1021. Acesso em: 22 jul. 2024.