Citation Chaser
Enter up to five DOIs for articles you already trust and get two lead lists: backward, the works each article cites, and forward, the works that have cited it since. Download either list as RIS, or both, and screen them alongside your database results. The data comes from OpenAlex. Free, no sign-up.
Up to 5 DOIs. Each is looked up on OpenAlex, then its reference list and its citing works are fetched, 100 to a request.
Pressing the button sends the DOIs, and then OpenAlex work IDs, from your browser to api.openalex.org, OpenAlex's public API. Nothing goes to CitationEasy and nothing is saved. OpenAlex gives keyless visitors a small daily budget shared by everyone on the same network, so a chase costs a handful of requests, not hundreds.
Paste one to 5 DOIs and press Chase citations.
How to Use the Citation Chaser
- 1. Paste your seed DOIs. One per line, up to five, as
10.1371/journal.pone.0115253,doi:10.…orhttps://doi.org/…. Pick articles you already know are relevant — the included studies from a first search, or a landmark paper on your topic. - 2. Choose the forward order. Each seed's citing works are fetched 100 to a page, up to 200 per seed. If a seed has more than that, choose whether you want the newest 200 or the most-cited 200.
- 3. Press Chase citations. Your browser asks OpenAlex for each seed, then for the works it cites, then for the works that cite it. A counter shows the request in progress, and you can stop at any time.
- 4. Read and export. Switch between the backward and forward lists. Each row shows the title, authors, year, journal, DOI and OpenAlex citation count, and — with several seeds — how many of your seeds it is linked to. Download RIS, copy the DOIs, or copy the table.
Backward and Forward Citation Searching
A database search finds papers by their words. Citation searching finds them by their relationships, which catches studies that use different vocabulary from your search string. There are two directions:
- Backward — look through a seed's reference list for earlier work it builds on. It finds older studies and the sources the authors considered essential.
- Forward — find the later papers that cite the seed. It finds newer studies, replications, critiques and updates that no reference list can contain yet.
Checking reference lists and citation searching are standard supplementary search methods in systematic reviews, and the Cochrane Handbook describes them among the ways to extend a database search. PRISMA 2020 asks you to report every source you searched, reference lists included, and the date you searched it — which is why the tool writes a one-paragraph search record for your methods section.
A Worked Example
The seed below is the 2014 PLOS ONE paper on reference rot cited in the Open Access Finder's example. These are the figures OpenAlex returned on 16 October 2026; they change as OpenAlex adds citations.
| Seed | Backward list | Forward list |
|---|---|---|
| 10.1371/journal.pone.0115253 — “Scholarly Context Not Found: One in Five Articles Suffers from Reference Rot” | 39 references listed by OpenAlex, all 39 found in OpenAlex | 178 citing works, fetched in two pages of 100 (OpenAlex's citation count for the paper reads 184, because the count and the list are updated separately) |
Add a second seed and a new column appears: Seeds linked shows how many of your seeds a work is tied to. A study that three of your five seeds cite, or that cites three of them, is a better candidate than one linked to a single seed, so the lists are sorted by that number first and by citation count second.
What the Lists Do and Do Not Tell You
- They are leads, not included studies. Every record still goes through your title and abstract screening, with the same eligibility criteria as the database results.
- They are OpenAlex's view. OpenAlex builds a paper's reference list from publisher metadata and text extraction, so the list can be shorter than the printed one — the Hirsch h-index paper, for one, lists only four. Web of Science, Scopus and Google Scholar will show different counts.
- Forward chasing is capped. At most 200 citing works per seed are fetched, which is why you choose newest or most-cited. A very highly cited seed needs a narrower approach, such as a keyword search within its citing works in a database.
- Backward chasing is capped too. Across all seeds, at most 500 references are fetched, those linked to the most seeds first.
- Duplicates are not removed against your database results. Import the RIS into your reference manager and deduplicate there.
What Is Sent, and Where
The tool runs in your browser, and when you press the button it talks to one service: OpenAlex's public API at api.openalex.org. The DOIs you entered go first, then OpenAlex work IDs taken from the answers. A request carries CitationEasy's support address as a courtesy to OpenAlex, never yours, and no account or key. Nothing goes to CitationEasy, and nothing is saved after you leave the page.
OpenAlex gives keyless visitors a small daily budget — at the time of writing, about 1,000 list requests a day, shared by everyone on the same network, with seed lookups free. A one-seed chase takes a few list requests — three for the example above. If you share a university network and see errors, try again later.
Frequently Asked Questions
- What is citation chasing?
- Citation chasing is a literature search that follows citations instead of keywords. Backward chasing reads the reference lists of key papers; forward chasing finds the papers that cite them. It is a standard supplement to database searching in systematic reviews.
- What is the difference between backward and forward citation searching?
- Backward searching moves back in time from a paper to the works it cites. Forward searching moves forward to the works that cite it. Together they map a paper's neighbourhood: its roots and its descendants.
- How many seed articles should I use?
- Use the articles you are most confident are relevant: typically your included studies, or a handful of landmark papers. This tool takes up to five at a time to stay within OpenAlex's free budget; for a longer list, run it in batches and combine the RIS files in your reference manager.
- Is OpenAlex as complete as Web of Science, Scopus or Google Scholar?
- It is open and wide in coverage, but its reference lists and citation counts differ from those of the commercial indexes, and sometimes from the paper itself. For a formal systematic review, many teams chase in more than one source and report which they used.
- Why does the forward list have fewer works than the citation count?
- The count is OpenAlex's running total for the paper, while the list is what its search can return, with your seed articles removed. The two are updated separately and can differ by a few works.
- How do I report citation chasing in a PRISMA flow diagram?
- PRISMA 2020 lets you report records from other methods, such as citation searching, as a separate stream in the flow diagram, next to the database stream. Copy the search record the tool writes into your methods, and enter the counts in the PRISMA Flow Diagram Generator.
- Does this tool send my DOIs to CitationEasy?
- No. Your browser sends them straight to OpenAlex, and CitationEasy neither sees nor stores them.