MURDOCH, D. Venn Diagrams in R. Journal of Statistical Software, Code Snippets, [S. l.], v. 11, n. 1, p. 1–3, 2004. DOI: 10.18637/jss.v011.c01. Disponível em: https://www.jstatsoft.org/index.php/jss/article/view/v011c01. Acesso em: 9 dec. 2021.