PEBESMA, E.; BIVAND, R.; RIBEIRO, P. J. Software for Spatial Statistics. Journal of Statistical Software, [S. l.], v. 63, n. 1, p. 1–8, 2015. DOI: 10.18637/jss.v063.i01. Disponível em: https://www.jstatsoft.org/index.php/jss/article/view/v063i01. Acesso em: 30 nov. 2021.