WANG, T.; MERKLE, E. C. merDeriv: Derivative Computations for Linear Mixed Effects Models with Application to Robust Standard Errors. Journal of Statistical Software, Code Snippets, [S. l.], v. 87, n. 1, p. 1–16, 2018. DOI: 10.18637/jss.v087.c01. Disponível em: https://www.jstatsoft.org/index.php/jss/article/view/v087c01. Acesso em: 21 may. 2022.