To cite merDeriv in publications use:

Wang T, Merkle EC (2018). “merDeriv: Derivative Computations for Linear Mixed Effects Models with Application to Robust Standard Errors.” Journal of Statistical Software, Code Snippets, 87(1), 1–16. doi:10.18637/jss.v087.c01.

Corresponding BibTeX entry:

  @Article{,
    title = {{merDeriv}: Derivative Computations for Linear Mixed
      Effects Models with Application to Robust Standard Errors},
    author = {Ting Wang and Edgar C. Merkle},
    journal = {Journal of Statistical Software, Code Snippets},
    year = {2018},
    volume = {87},
    number = {1},
    pages = {1--16},
    doi = {10.18637/jss.v087.c01},
  }