To cite behaviorchange in publications use:

Peters G, Crutzen R, Gruijters S (2022). The behaviorchange Package: Tools for Behavior Change Researchers and Professionals. https://r-packages.gitlab.io/behaviorchange.

Corresponding BibTeX entry:

  @Manual{,
    title = {The behaviorchange Package: Tools for Behavior Change
      Researchers and Professionals},
    author = {Gjalt-Jorn Ygram Peters and Rik Crutzen and Stefan
      Gruijters},
    year = {2022},
    url = {https://r-packages.gitlab.io/behaviorchange},
  }