Toad Encased in an Elm Tree (sources)
- Histoire de l'Academie Royale des Sciences, Annee M. DCCXIX (for the year 1719), published 1721, France. Pgs. 39-40. Online [in French]: https://books.google.com/books?id=jU5rsHJ8EhgC&pg=PA40&dq=%22Histoire+de+l%27Academie+Royale+des+Sciences%22+Hubert+varignon&hl=en&sa=X&ved=0ahUKEwih86GZx6DWAhWH0J8KHaIsApYQ6AEILjAB#v=onepage&q=%22Histoire%20de%20l%27Academie%20Royale%20des%20Sciences%22%20Hubert%20varignon&f=false
Mentions & Repeaters
- Phenomena: A Book of Wonders, by John Michell & Robert J.M. Rickard, 1977 Pantheon Books, New York, USA. ISBN: 0-394-73389-4. Pgs. 70-71