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
grandfather Jacob Sebastians van den Berch (1566-1615), brewer in de Klock, buried in Oude Kerk
DTB Delft inv. 37, fol. 15v