To cite ssmrob in publications use:

Zhelonkin M, Ronchetti E (2021). “Robust Analysis of Sample Selection Models through the R Package ssmrob.” Journal of Statistical Software, 99(4), 1–35. doi:10.18637/jss.v099.i04.

Corresponding BibTeX entry:

  @Article{,
    title = {Robust Analysis of Sample Selection Models through the {R}
      Package {ssmrob}},
    author = {Mikhail Zhelonkin and Elvezio Ronchetti},
    journal = {Journal of Statistical Software},
    year = {2021},
    volume = {99},
    number = {4},
    pages = {1--35},
    doi = {10.18637/jss.v099.i04},
  }