To cite codebook in publications use:

Arslan, R. C. (2018). How to automatically generate rich codebooks from study metadata. PsyArXiv.<doi:10.31234/osf.io/5qc6h>

Corresponding BibTeX entry:

  @Misc{,
    title = {How to automatically generate rich codebooks from study
      metadata.},
    author = {Ruben C. Arslan},
    year = {2018},
    doi = {10.31234/osf.io/5qc6h},
    publisher = {PsyArxiv},
    url = {https://doi.org/10.31234/osf.io/5qc6h},
    note = {Software package},
  }