ZAHRAN, A. R.; ABD EL-SAMEA, N. A.; NAFEA, R. A. A Reduced Wealth Index for Phone Polls. Asian Journal of Empirical Research, [S. l.], v. 3, n. 4, p. 433–446, 2013. Disponível em: https://archive.aessweb.com/index.php/5004/article/view/3375. Acesso em: 5 may. 2024.