To cite the RSiena package in publications use:

Ripley RM, Snijders TAB, B'oda Z, V"or"os A, Preciado P (2020). “Manual for Siena version 4.0.” Oxford: University of Oxford, Department of Statistics; Nuffield College. R package version 1.2-23. https://www.cran.r-project.org/web/packages/RSiena/.

Corresponding BibTeX entry:

  @TechReport{,
    title = {Manual for {Siena} version 4.0},
    author = {Ruth M. Ripley and Tom A. B. Snijders and Zsofia B'{o}da
      and Andr'{a}s V"{o}r"{o}s and Paulina Preciado},
    year = {2020},
    institution = {Oxford: University of Oxford, Department of
      Statistics; Nuffield College},
    note = {R package version 1.2-23.
      https://www.cran.r-project.org/web/packages/RSiena/},
  }