To cite 'modelbased' in publications use:

  Makowski, D., Ben-Shachar, M. S., Patil, I., & Lüdecke, D. (2020).
  Estimation of Model-Based Predictions, Contrasts and Means. CRAN.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {Estimation of Model-Based Predictions, Contrasts and Means.},
    author = {Dominique Makowski and Mattan S. Ben-Shachar and Indrajeet Patil and Daniel Lüdecke},
    journal = {CRAN},
    year = {2020},
    url = {https://github.com/easystats/modelbased},
  }