doublet achromatique
1996 / New Light on the Invention of the Achromatic Telescope Objective / R. Willach / Notes and Records 50 (1996) p. 195 [doi]
2001 / Dollond & Son's Pursuit of Achromaticity, 1758-1789 / Richard Sorrenson / History of Science 39 (2001) p. 31 [lien]