Links related to the Düben Collection Database Catalogue
Jan Olof Rudén: Vattenmärken och Musikforskning (Watermarks and Musicology)
In 1968 Jan Olof Rudén investigated watermarks of type "Narr" used in the Düben Collection.
This is one of the most important contributions to the chronology of the Düben Collection.
A scanned version of the dissertation (in Swedish, with a summary in German) can be found