zotero_harvester.conf: Added 2516-6301 (see ubtue/DatenProbleme#639)
zotero_harvester.conf: Added 2516-6301 (see ubtue/DatenProbleme#639)

ubtue/ub_tools,ubtue/ub_tools,ubtue/ub_tools,ubtue/ub_tools,ubtue/ub_tools,ubtue/ub_tools,ubtue/ub_tools,ubtue/ub_tools