To cite REndo in publications use:

  Gui R, Meierer M, Schilter P, Algesheimer R (2023). “REndo: Internal
  Instrumental Variables to Address Endogeneity.” _Journal of
  Statistical Software_, *107*(3), 1-43. doi:10.18637/jss.v107.i03
  <https://doi.org/10.18637/jss.v107.i03>.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {{REndo}: Internal Instrumental Variables to Address Endogeneity},
    author = {Raluca Gui and Markus Meierer and Patrik Schilter and Ren\'e Algesheimer},
    journal = {Journal of Statistical Software},
    year = {2023},
    volume = {107},
    number = {3},
    pages = {1--43},
    doi = {10.18637/jss.v107.i03},
  }