SINGH, H. P.; RATHOUR, A.; SOLANKI, R. S. Improved class of estimators of finite population mean using sampling fraction and information on two auxiliary variables in sample surveys. Statistica, [S. l.], v. 73, n. 3, p. 353–361, 2013. DOI: 10.6092/issn.1973-2201/4329. Disponível em: https://rivista-statistica.unibo.it/article/view/4329. Acesso em: 1 feb. 2023.