To cite taxize in publications use at least the first, if not both:

Scott Chamberlain, Eduard Szocs (2013). “taxize - taxonomic search and retrieval in R.” F1000Research. https://f1000research.com/articles/2-191/v2.

Chamberlain S, Szoecs E, Foster Z, Arendsee Z, Boettiger C, Ram K, Bartomeus I, Baumgartner J, O'Donnell J, Oksanen J, Tzovaras BG, Marchand P, Tran V, Salmon M, Li G, Grenié M (2020). taxize: Taxonomic information from around the web. R package version 0.9.98, https://github.com/ropensci/taxize.

Corresponding BibTeX entries:

  @Article{,
    title = {taxize - taxonomic search and retrieval in R},
    journal = {F1000Research},
    author = {{Scott Chamberlain} and {Eduard Szocs}},
    year = {2013},
    url = {https://f1000research.com/articles/2-191/v2},
  }

  @Manual{,
    title = {taxize: Taxonomic information from around the web},
    author = {Scott Chamberlain and Eduard Szoecs and Zachary Foster
      and Zebulun Arendsee and Carl Boettiger and Karthik Ram and
      Ignasi Bartomeus and John Baumgartner and James O'Donnell and
      Jari Oksanen and Bastian Greshake Tzovaras and Philippe Marchand
      and Vinh Tran and Maëlle Salmon and Gaopeng Li and Matthias
      Grenié},
    year = {2020},
    note = {R package version 0.9.98},
    url = {https://github.com/ropensci/taxize},
  }