Letter from John Albert Euler to Jean Henri Samuel Formey (Saint Petersburg, 21 October 1767). Ed. by Emmanuelle Chaze. In: "Letters and texts: Intellectual Berlin around 1800". Ed. by Anne Baillot. Berlin: Humboldt-Universit├Ąt zu Berlin. http://www.berliner-intellektuelle.eu/manuscript?Brief18vonJAEuleranJHSFormey. Last modified: 12 May 2014.