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Library Services




Guide to using Mendeley reference management and social citation sharing software

Managing duplicate references

If you have imported references on the same subject from more than one online resource, you may find that you have some duplicate references in your library. It is important to remove duplicates if you intend to use Mendeley with Word to cite references, to avoid errors in your bibliography.

Automatic duplicate search

Mendeley will automatically search the whole Mendeley Library, for duplicates.

Mendeley also automatically creates a smart collection called 'Duplicates'. The duplicates are grouped as individual sets of duplicates. If you wish to delete one of the duplicates (recommended), then select the 'trash' icon.

Note: The duplicate criterion, is based on the DOI (Digital Object Identifier) of the relevant references, and not on other criteria such as title, author or year. Many reference records don't contain DOIs, and in some cases some references have the same DOI included in the record, so this method does not guarantee all duplicates will be identified, and some duplicates my not be duplicates after all. 

Manual de-duplication

To catch any outstanding duplicates it can be helpful to manually look through your library.

  • Make sure to organise your centre pane where your references are displayed so that you can see all the useful fields clearly to help you judge whether a reference is a true duplicate.
  • It can also be useful to set your output style to Annotated so that the reference preview includes the abstract.
  • Sort your references by the Title field by clicking on the column header. You can then look through to check for duplicate titles - although be aware that sometimes different publications can have the same title.