synonyms for plants and animals.

• Wikispecies <- Wikispecies
• ITIS = Integrated Taxonomic Information System, ITIS
• EOL = Encyclopedia of Life
• Catalogue of Life = Catalogue of Life

• UK species from NHM

• Avibase <- Avibase

• The Plant List - The Plant List, now World Flora Online: website

(examples)

• Black redstart—Ruticilla titys (Scop.):
  Bonhote, J. Lewis (1907). Birds of Britain. illustrated by H.E. Dresser. London: Adam and Charles Black. p. 33. OCLC 1451688 (all editions). Retrieved 2020-05-19.
• Great reed warbler—Acrocephalus turdoïdes:
  Gould, John (1873). The Birds of Great Britain. Vol. II. pp. Plate LXXII (and accompanying text). OCLC 752452823 (all editions). Retrieved 2020-05-19.
• ditto:
  Digital Collections, The New York Public Library. "(still image) Acrocephalus turdoïdes. Thrush-Warbler (1862 - 1873)". The New York Public Library, Astor, Lennox, and Tilden Foundation. Retrieved July 17, 2019.
• Eurasian scops owl—Scops giu (Scop., 1766):
  Powys, 4th Baron Lilford, Thomas Littleton; Salvin, Osbert; Newton, Alfred; Keulemans, John Gerrard (1885). Coloured figures of the birds of the British Islands. Vol. 1. London: R.H. Porter. pp. 98f. OCLC 1029665771 (all editions). Retrieved 2020-05-15.{{cite book}}: CS1 maint: numeric names: authors list (link)