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A free tool for researchers & students

Combine RIS files

Combine RIS exports, find missing DOIs, detect duplicates, and produce clean citation sets that make PRISMA and literature-review reporting simpler.

Start a cleanup See how it works
  1. 1. Upload Citations as RIS Files
  2. 2. Duplicates Identified & Removed
  3. 3. Download Results (RIS & XLSX) & View Report

"So much simpler than managing duplicates in EndNote"

- Jen, Sydney, Australia

"Thank you from Singapore. It was easy to combine my files"

- Priya, Singapore

Upload your files

Upload RIS exports from your databases or reference managers, find missing DOIs, remove duplicates, and download clean sets for PRISMA-style reporting.

  • RIS from Scholar, EndNote, Zotero, Mendeley, Scopus, WoS, and more
  • PubMed .nbib exports also supported
  • DOI lookup via local OpenAlex data
  • Six outputs: unique, duplicates removed, and unknown (RIS + Excel)
  • Up to 5 files / 50,000 citations / 100MB total filesize.
Required. We'll let you know once your files are ready. Comma separate multiple addresses.

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RIS (.ris) from Google Scholar, EndNote, Mendeley, Zotero, Scopus, Web of Science, Cochrane, EBSCOhost, Embase, and others, or PubMed (.nbib). Up to 5 files / 50,000 citations / 100MB total filesize.
Optional. Helps label citations in your report and exports.

What you get

Built for systematic and literature reviews: merge database exports, remove duplicates transparently, and document every step for your methods section.

Upload RIS (and PubMed)

Combine .ris files from Google Scholar, EndNote, Mendeley, Zotero, Scopus, Web of Science, Cochrane, EBSCOhost, Embase, and more, plus PubMed .nbib.

Find missing DOIs

Keep DOIs already in your files, then look up missing ones from local OpenAlex data so duplicates can be matched more reliably.

Detect duplicates

Auto-remove records that share the same DOI.

Six ready-to-use files

Download unique citations, duplicates removed, and unknown (no DOI), each as RIS and Excel, with the original filename on every row.

PRISMA-friendly report

Every job gets a shareable URL with flow counts you can cite when describing identification and deduplication.

Auto-delete in 7 days

Uploads and outputs expire automatically, built for privacy-minded research workflows.

How it works

From database export to PRISMA-ready counts in four steps.

  1. 1
    Search your databases
    Scopus, Web of Science, PubMed, Embase, Cochrane, and more.
  2. 2
    Export as RIS (or PubMed .nbib)
    From the database itself or via EndNote, Zotero, or Mendeley.
  3. 3
    We combine, enrich & dedupe
    Missing DOIs filled where possible; duplicates flagged and removed with a clear audit trail.
  4. 4
    Download & report
    Six files (RIS & Excel) plus a PDF report with PRISMA-style identification counts. A report also available online.
Get started free

FAQ

Quick answers about cost, what the tool does, and how your data is handled.

Is this tool free?

Yes. Researcher's Friend is free to use. You can process up to 5 files and 50,000 citations per job at no charge.

What does this tool do?

It combines RIS (and PubMed .nbib) exports, finds missing DOIs, detects duplicates, and gives you six downloadable files: unique citations, duplicates removed, and unknown (no DOI), each as RIS and Excel, plus a shareable PRISMA-style report.

What problem does the tool solve?

Literature searches across multiple databases produce overlapping results. Manually merging files and justifying duplicate removal for PRISMA reporting is slow and error-prone. This tool automates combination, DOI enrichment, and transparent deduplication so your methods section is easier to write.

How long are my data available?

The files we generate for you are available for 7 days, then are automatically deleted. Public reports are available indefinitely.

What files am I provided from my RIS files?

You are emailed a link to download a zip file which contains six files (data are provided in both RIS and Excel filetypes): 'unique_citations' are citations that are unique (based on DOI), 'duplicates_removed' are the duplicate citations removed (there will be one of each citation in this file in 'unique_citations'), and 'unknown' which are records where we were unable to determine if the citations were duplicates (i.e. you need to confirm that the citations in this file are not duplicates, and include them in your corpus once you've confirmed that they are not duplicates).

Who are you?

Gary Eckstein (Ph.D., M.B.A.) is an Australian academic. See more at https://www.linkedin.com/in/eckstein/

How can I get the best results?

Please include as many DOIs for your citations as possible. This will signiciantly improve your results. Click for instructions for EndNote, and Mendeley.

How are duplicates identified?

The DOI is used as identifier. If two citations have the same DOI, they are considered duplicates.

What don't some of my citations include DOI?

Based on the publication year, first author surname, and title we search local OpenAlex parquet snapshots. Title matching uses Levenshtein similarity at 90% (very close match).

Are my data stored? Where is the data processed?

The data you upload (e.g. RIS files) are stored for the duration of processing (usually a few minutes). Your report is available on an ongoing basis (there is no identifying information in the report). The files we produce for you (RIS and Excel) are stored for 7 days. The email addresses of our users are stored for reporting purposes. No identifying information provided to us is shared with third parties. Processing and storage is performed in Australia.

How do export RIS from Endnote?

  1. Open EndNote and select the references you want to export.
  2. Click 'File' > 'Export' from the top menu.
  3. Choose a destination folder and type a file name.
  4. Set 'Save as type' to 'Text File (*.txt)'.
  5. Set 'Output style' to 'RefMan (RIS) Export'. If it does not appear in the dropdown menu, click 'Select Another Style...' and search for 'RefMan (RIS) Export'.
  6. Click Save.
  7. Locate the saved .txt file and rename the file extension from .txt to .ris.

How do I cite this app?

Please cite as
Eckstein, Gary. 'Researchers Friend'. Making Literature Selection More Accurate, 2026, https://researchersfriend.org.
The citation RIS file for EndNote, Mendley, Zotero etc. is available here.