To cite taxadb in publications use:

Norman KEA, Chamberlain S, Boettiger C (2020). “taxadb: A high-performance local taxonomic database interface.” Methods in Ecology and Evolution, 11(9), 1153–1159.

Corresponding BibTeX entry:

  @Article{,
    title = {taxadb: A high-performance local taxonomic database
      interface},
    author = {Kari E. A Norman and Scott Chamberlain and Carl
      Boettiger},
    journal = {Methods in Ecology and Evolution},
    year = {2020},
    volume = {11},
    number = {9},
    pages = {1153--1159},
  }