{{cite web |url=https://marcus.uib.no/instance/webresource/d67d16e4-dc2a-4b2c-9a1a-3b130c670924 |title=Thon, Theodor: Handbuch für Naturaliensammler oder gründliche Anweisung [...] |author=Avdeling for spesialsamlinger |accessdate=Sun Jul 12, 2026 |publisher=University of Bergen Library}}