To cite package "PsychroLib" in publications use:

Meyer D, Thevenard D (2019). “PsychroLib: a library of psychrometric functions to calculate thermodynamic properties of air.” Journal of Open Source Software, 4(33), 1137. doi: 10.21105/joss.01137.

Corresponding BibTeX entry:

  @Article{,
    title = {{PsychroLib}: a library of psychrometric functions to
      calculate thermodynamic properties of air},
    author = {D. Meyer and D. Thevenard},
    journal = {Journal of Open Source Software},
    publisher = {The Open Journal},
    volume = {4},
    number = {33},
    pages = {1137},
    year = {2019},
    doi = {10.21105/joss.01137},
  }