Volumes 1 through 20 of Alle de Brieven / Collected Letters, the complete series. Download for free.
Master list (pdf) of all 602 L-numbers, their Leeuwenhoek number, and their Collected Letters number
nephew Jacob Jans de Molijn baptized in Oude Kerk. His mother was Leeuwenhoek's sister Margrieta.
DTB Delft inv. 9, fol. 167v