GUPTA, J. P.; SINGH, R. A note on usual correlation coefficient in systematic sampling. Statistica, [S. l.], v. 50, n. 2, p. 255–259, 1990. DOI: 10.6092/issn.1973-2201/837. Disponível em: https://rivista-statistica.unibo.it/article/view/837. Acesso em: 2 dec. 2021.