If you wish to delete ALL references in your Project, this can be accomplished by going into Project > Bulk Delete. Entering the command: delete_all_references_and_data into the submission box and clicking on the green Submit button will delete all references*.
If you wish to delete only specific references, this can be done through Datarama. In the Reference Criteria tab of Datarama, you can enter the RefIDs that you wish to delete into the RefID field and click Run Report. A report listing those references will be displayed on the screen. Scroll down to the bottom of the report and on the bottom right side of the screen will be an option to "Permanently Delete # References". Clicking this button will delete the references listed in your report*.
The following link from our online User Guide provides additional information on reference deletion:
* Note that this is a permanent bulk removal and cannot be undone.