Person Blum, Robert male Permanent URL https://www.proveana.de/en/link/act00000057 last updated 30.07.2020 Show sources Hide sources Network Network Person/Corporate bodies Freundschaft Show sources Freundschaftlicher Kontakt zu Ludwig Armbruster. Armbruster, Ludwig Research reports Provenance research on the Armbruster collection31.10.2016 References References Research projects Project reference Provenance research on the Armbruster collection