Wang T, Merkle EC. merDeriv: Derivative Computations for Linear Mixed Effects Models with Application to Robust Standard Errors. J. Stat. Soft. [Internet]. 2018 Nov. 30 [cited 2024 Apr. 26];87(1):1-16. Available from: https://www.jstatsoft.org/index.php/jss/article/view/v087c01