拉朗德
The Paris Observatory library preserves a great number of original works and letters of the Observatory and well known astronomers. The entire collection has been inventoried in an online archive called "Alidade" - Accès en Ligne aux Instruments, Documents et Archives De l’astronomiE (Online Access to Instruments, Documents and Archives of Astronomy). Some of the work is now digitized on the digital library such as those of Johannes Hevelius, Jérôme Lalande and Joseph-Nicolas Delisle.