To cite geex in publications use:

Saul BC, Hudgens MG (2020). “The Calculus of M-Estimation in R with geex.” Journal of Statistical Software, 92(2), 1–15. doi:10.18637/jss.v092.i02.

Corresponding BibTeX entry:

  @Article{,
    title = {The Calculus of M-Estimation in {R} with {geex}},
    author = {Bradley C. Saul and Michael G. Hudgens},
    journal = {Journal of Statistical Software},
    year = {2020},
    volume = {92},
    number = {2},
    pages = {1--15},
    doi = {10.18637/jss.v092.i02},
  }