1. Methodus nova accurata & facilis inveniendi radices æqnationum quarumcumque generaliter, sine praviæ reductione
2. N. Nielsen, Géomètres français de dix-huitième siècle, edited by N. E. Norlund, Copenhague, Levin & Munksgaard, 1935, pp. 240–248, Gauthier-Villars, Paris. I am indebted to this book for the reference to the book of de Lagny and its relation with Halley's paper in the Philosophical Transactions. It was while a search was being made at the Huntington Library for the number of the Transactions which contains Halley's paper that my friend Mr. Ronald Coonrod found that an account of Halley's work was contained in “Miscellanea Curiosa.”
3. R. Dedekind, Stetigkeit und irrationale Zahlen, Brunswick, 1872.
4. Sur la racine carrée des nombres