HANKIN, R. K. S.; WEST, L. J. Set Partitions in R. Journal of Statistical Software, Code Snippets, [S. l.], v. 23, n. 2, p. 1–12, 2007. DOI: 10.18637/jss.v023.c02. Disponível em: https://www.jstatsoft.org/index.php/jss/article/view/v023c02. Acesso em: 4 dec. 2022.