1. Darwin, C. On the Origin of Species (John Murray, London, 1859).
2. GenBank (National Institutes of Health);
https://www.ncbi.nlm.nih.gov/genbank/
3. Hinchliff, C. E. et al. Synthesis of phylogeny and taxonomy into a comprehensive tree of life. Proc. Natl Acad. Sci. USA 112, 12764–12769 (2015).
4. GBIF (Global Biodiversity Information Facility);
https://www.gbif.org/
5. iDigBio (National Science Foundation);
https://www.idigbio.org/