VARADHAN, R. Numerical Optimization in R: Beyond optim. Journal of Statistical Software, [S. l.], v. 60, n. 1, p. 1–3, 2014. DOI: 10.18637/jss.v060.i01. Disponível em: https://www.jstatsoft.org/index.php/jss/article/view/v060i01. Acesso em: 3 dec. 2022.