KETTLE, Sally. Meet Jonathan, St Helena's 182-year-old giant tortoise. BBC News [online]. 2014-03-13 [cit. 2016-01-01]. Dostupné online.
dailymail.co.uk
Jonathan the 176-year-old tortoise revealed as world's oldest animal in Boer War photo. Daily Mail [online]. 2008-12-05 [cit. 2016-01-01]. Dostupné online.
saint.fm
independent.saint.fm
PIPE, Simon. Jonathan’s birthday... what ancient history never taught us. S. 5. The St Helena Independent [online]. 2015-02-06. Roč. 10, čís. 9, s. 5. Dostupné online.[nedostupný zdroj]
sainthelenaisland.info
Notes and coins of St. Helena [online]. [cit. 2016-01-01]. Dostupné online.