https://api.elsevier.com/content/abstract/citations?pubmed_id=3472723&apiKey={API_KEY}&httpAccept=application/json
curl -H 'Accept:application/json' -H "X-ELS-APIKey: $API_KEY" 'https://api.elsevier.com/content/abstract/citations?pubmed_id=3472723
https://api.elsevier.com/content/abstract/citation-count?pubmed_id=3472723&apiKey=6492f9c867ddf3e84baa10b5971e3e3d
(API key from developer documentation)
https://api.elsevier.com/content/search/index:SCOPUS?query=PMID(3472723)&apiKey={API_KEY}&instToken={INST_TOKEN}&httpAccept=application/json