BOWMAN, A.; GIBSON, I.; SCOTT, E. M.; CRAWFORD, E. Interactive Teaching Tools for Spatial Sampling. Journal of Statistical Software, [S. l.], v. 36, n. 13, p. 1–17, 2010. DOI: 10.18637/jss.v036.i13. Disponível em: https://www.jstatsoft.org/index.php/jss/article/view/v036i13. Acesso em: 17 aug. 2022.