To cite 'hydroPSO' in publications use:

Zambrano-Bigiarini, M., Rojas, R. (2013). “A model-independent Particle Swarm Optimisation software for model calibration.” Environmental Modelling & Software, 43, 5-25. doi: 10.1016/j.envsoft.2013.01.004, http://dx.doi.org/10.1016/j.envsoft.2013.01.004.

Zambrano-Bigiarini M, Rojas R (2020). hydroPSO: Particle Swarm Optimisation, with Focus on Environmental Models. R package version 0.5-1 . doi:10.5281/zenodo.1287350, https://CRAN.R-project.org/package=hydroPSO.

Corresponding BibTeX entries:

  @Article{Zambrano-BigiariniRojas2013-hydroPSO_article,
    title = {A model-independent Particle Swarm Optimisation software
      for model calibration},
    journal = {Environmental Modelling & Software},
    author = {{Zambrano-Bigiarini} and {M.} and {Rojas} and {R.}},
    volume = {43},
    pages = {5-25},
    year = {2013},
    doi = {10.1016/j.envsoft.2013.01.004},
    url = {http://dx.doi.org/10.1016/j.envsoft.2013.01.004},
  }

  @Manual{Zambrano-BigiariniRojas-hydroPSO_pkg,
    title = {hydroPSO: Particle Swarm Optimisation, with Focus on
      Environmental Models},
    author = {Mauricio Zambrano-Bigiarini and Rodrigo Rojas},
    year = {2020},
    note = {R package version 0.5-1 . doi:10.5281/zenodo.1287350},
    url = {https://CRAN.R-project.org/package=hydroPSO},
  }