If you wish to delete only specific references uploaded on a certain date, you can do so through Datarama. Navigate to Reports > Datarama and go to the Reference Display Options tab. Under the "Reference Fields" section, select distiller_reference_upload_date and click Run Report. Take a note of the RefIDs that fall within the date or date range you want to delete. If there is a large number of references that fall within the date or date range, you can export the report as an Excel file, sort by date in the exported file, and copy the corresponding RefIDs that way.
In the Reference Criteria tab of Datarama, you can enter the RefIDs of those references into the RefID field and click Run Report. This will display a report listing those references. Scroll down to the bottom of the report and there will be an option to "Permanently Delete # References". Clicking this button will delete the references listed in your report.