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Importing references

How to import grey literature

Last updated on 28 Sept, 2026

Covidence allows you to include grey literature alongside references from bibliographic databases. Because grey literature may not be available in a standard database format, you will generally need to create a citation for each item before importing it into Covidence.

The easiest way to do this is with a reference manager such as Zotero or EndNote.

1. Create a citation for your grey literature

First, create a reference for each grey literature item in your reference manager.

When creating your records, consider selecting Journal Article as the Item Type in Zotero or the equivalent Reference Type in EndNote. These fields most closely match the metadata fields that Covidence uses when importing and deduplicating references, including the abstract field.

You may need to manually enter or edit the bibliographic information for your grey literature. Be sure to include as much relevant metadata as possible, particularly the title, authors, publication year, and abstract.

Including information in the abstract field is especially important because it allows this information to be displayed when you screen the reference in Covidence.

2. Export your references

Once your grey literature references have been created, export them from your reference manager in one of the following Covidence-compatible formats:

  • EndNote XML

  • RIS text

If you have multiple grey literature references, you can export them together in a single file.

3. Import your references into Covidence

In Covidence:

  1. Go to Import.

  2. Select the section of your review that you want to import the references into from the Import in to menu.

  3. Select "Grey literature" as your source.

  4. Import your exported reference file.

Selecting the appropriate section during import is important because the import will be reflected in your review's PRISMA flow diagram.

4. Add the full text

If a PDF is available, upload it to the reference in Covidence during full-text review.

If there is no PDF available, you can add a URL to the grey literature record instead. During full-text review, use the Upload full-text button to add the available URL to the reference.

How to video:

If you cannot import the grey literature as references

If you are unable to create Covidence-compatible reference records for your grey literature, you can also account for these items manually in your PRISMA flow diagram.

At the end of your review, download the modifiable DOCX version of the PRISMA diagram and manually add the number of records identified from other sources, such as grey literature.

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