1. This ascription is found in other sources also: George Salmon, Higher Plane Curves, 3rd ed., London, 1879, pp. 368–369; E. J. Wilczynski, Some remarks on the historical development and the future prospects of the differential geometry of plane curves, Bull. Amer. Math. Soc. vol. 22, 1915- 1916 pp. 320–324 (especially p. 321); Encyklopädie der Mathematischen Wissenschaften, III, vol. 3, p. 40.
2. Géométrie de position, Paris, 1803, pp. 475 f.
3. The Differential Equation of a Conic and Its Relation to the Aberrancy