curl --request POST \
  --url https://api.anysite.io/api/europepmc/articles/citations \
  --header 'Content-Type: application/json' \
  --header 'access-token: <api-key>' \
  --data '
{
  "id": "<string>",
  "count": 2,
  "timeout": 300,
  "source": "MED"
}
'

[
  {
    "id": "<string>",
    "@type": "@europepmc_citation",
    "source": "<string>",
    "title": "",
    "author_string": "<string>",
    "citation_type": "<string>",
    "journal_abbreviation": "<string>",
    "pub_year": 123,
    "volume": "<string>",
    "issue": "<string>",
    "page_info": "<string>",
    "cited_order": 123,
    "issn": "<string>",
    "essn": "<string>",
    "is_match": false,
    "cited_by_count": 0
  }
]