There is a duplication checker available in your reference list. You can click a button and get a list of the references that are duplicated in a new tab. Access this feature from the 'Add references' menu.
If the list is empty, it means we did not find any.
Both (all) references will show if there is a duplication, not just the duplicated. That is so you can choose which one to delete.
When you have found the references you want to delete, you can use the control + F search feature in your browser to find them in your reference list.
Go to the reference list, hold the "control" and "F" buttons on your keyboard down at the same time, and the search box will appear. Then you can copy in the name of the reference in the search box, click enter/search, and it will show you the hits in the list.
This is not a very advanced deduplication tool, like you can find in systematic review software, it is based on similarity of name, doi and pubmed ID.
There is also a "deduplication" warning- feature, to alert you when you upload new references that already exist. You will get an alert that tells you that you are trying to upload an existing reference.
Find the feature in the Guideline ->
See the duplicates ->
Use the search feature in your browser (control + F), to find the reference in the reference list->