To cite hockeystick in publications use:

Cortina H (2020). hockeystick: Download and Visualize Essential Climate Change Data. https://cortinah.github.io/hockeystick/.

Corresponding BibTeX entry:

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