https://www.epo.org/en/service-support/faq/searching-patents/open-patent-services/search-queries-tips-and-tricks/how-do-i
How do I find citations and cited documents via RESTful OPS?
To find citations, you have to do a search via the Published Data service, using a CQL request containing "ct" as in the following example:
To find cited documents, submit a request via the Published Data service, using the constituent "biblio" as in following example:
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