To cite metrica in publications use:

  Correndo, A.A., et al., (2022). metrica: an R package to evaluate
  prediction performance of regression and classification
  point-forecast models. Journal of Open Source Software, 7(79), 4655,
  https://doi.org/10.21105/joss.04655

A BibTeX entry for LaTeX users is

  @Article{,
    title = {metrica: an R package to evaluate prediction performance of regression and classification point-forecast models},
    author = {Adrian A. Correndo and Luiz H. Moro Rosso and Carlos H. Hernandez and Leonardo M. Bastos and Luciana Nieto and Dean Holzworth and Ignacio A. Ciampitti},
    journal = {Journal of Open Source Software},
    year = {2022},
    volume = {7},
    number = {79},
    pages = {4655},
    doi = {10.21105/joss.04655},
    url = {https://joss.theoj.org/papers/10.21105/joss.04655},
  }