To cite hockeystick in publications use:

Hernando Cortina. hockeystick: Download and Visualize Essential Climate Change Data (2020)

Corresponding BibTeX entry:

  @Manual{,
    title = {hockeystick: Download and Visualize Essential Climate
      Change Data},
    author = {Hernando Cortina},
    year = {2020},
    url = {https://cortinah.github.io/hockeystick/},
  }