Thomas Bewick: Memorial edition of Thomas Bewick's works. [w:] v. 1. A history of British birds. Land birds.--v. 2. A history of British birds. Water birds.--v. 3. A general history of quadrupeds.--v. 4. The fables of Aesop, and others.--v. 5. Memoir of Thomas Bewick, written by himself [on-line]. London, B. Quaritch. [dostęp 2017-04-26]. (ang.).
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William Yarrell: Alfred Newton Papers > William Yarrell: letters to him. [w:] Cambridge University Library: Manuscripts [on-line]. Janus (Janus provides access to more than 1800 catalogues of archives held throughout Cambridge). [dostęp 2017-04-23]. (ang.).
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Thomas Campbell Eyton: A History of the Rarer British Birds. Longman, Rees, Orme, Brown, Green, and Longman, 1836 (w formie cyfrowej: 9 maja 2006), s. 1–101.
