Although RefWorks has a tool to find Duplicate references, it might be safer to keep them than to delete one that you have already used in Write-N-Cite, or one that your are depending on having in several folders.
RefWorks has free add-ons available for Word and Google Docs. They allow you to add citations and automatically create bibliographies within Word or Google Docs. More info at the links below.
Help pages from RefWorks:
Oscar Rennebohm Library
959 Edgewood College Drive - Madison, WI 53711
608-663-3300