feat: text that explains citations count

Author: andreishket

vis/js/templates/modals/infomodal/PubMedInfo.tsx

@@ -16,16 +16,20 @@ const PubMedInfo = ({ params, isStreamgraph }) => {
       serviceName="PubMed"
       serviceDesc={
         <>
-          PubMed comprises more than 35 million citations for biomedical
+          PubMed comprises more than 38 million citations for biomedical
           literature from MEDLINE, life science journals, and online books. For
           more information please{" "}
-          <a
-            href="http://www.ncbi.nlm.nih.gov/pubmed"
-            target="_blank "
-          >
+          <a href="http://www.ncbi.nlm.nih.gov/pubmed" target="_blank ">
             visit the PubMed website
           </a>
           .
+          <br />
+          Citations are available for documents with a DOI and based on citation
+          data provided by{" "}
+          <a href="https://www.crossref.org/" target="_blank">
+            Crossref
+          </a>
+          . Results may be impacted by accuracy and completeness of this data.
         </>
       }
       params={params}