<a href="https://en.wikipedia.org/wiki/South_Africa" id="mwoA" rel="mw:WikiLink" title="South Africa">South African</a> medical researcher <a href="https://en.wikipedia.org/wiki/Max_Theiler" id="mwoQ" rel="mw:WikiLink" title="Max Theiler">Max Theiler</a> develops the <a href="https://en.wikipedia.org/wiki/Yellow_fever" id="mwog" rel="mw:WikiLink" title="Yellow fever">yellow fever</a> <a href="https://en.wikipedia.org/wiki/Vaccine" id="mwow" rel="mw:WikiLink" title="Vaccine">vaccine</a> at the <a href="https://en.wikipedia.org/wiki/Rockefeller_Foundation" id="mwpA" rel="mw:WikiLink" title="Rockefeller Foundation">Rockefeller Foundation</a> in <a href="https://en.wikipedia.org/wiki/New_York_City" id="mwpQ" rel="mw:WikiLink" title="New York City">New York</a>.<sup about="#mwt35" class="mw-ref reference" data-mw='{"name":"ref","attrs":{},"body":{"id":"mw-reference-text-cite_note-5"}}' id="cite_ref-5" rel="dc:references" typeof="mw:Extension/ref"><a href="./April_28#cite_note-5" id="mwpg" style="counter-reset: mw-Ref 5;"><span class="mw-reflink-text" id="mwpw">[5]</span></a></sup>
<span class="mw-reference-text" id="mw-reference-text-cite_note-5"><cite about="#mwt32" class="citation journal cs1" id="CITEREFFrierson2010">Frierson, J. (June 2010). <a class="external text" href="https://www.researchgate.net/publication/44853136" id="mwBmI" rel="mw:ExtLink nofollow">"The Yellow Fever Vaccine: A History"</a>. <i id="mwBmM">ResearchGate</i>. <b id="mwBmQ">83</b> (2): 77–85. <a class="mw-redirect" href="./PMC_(identifier)" id="mwBmU" rel="mw:WikiLink" title="PMC (identifier)">PMC</a><span id="mwBmY" typeof="mw:Entity"> </span><span class="id-lock-free" id="mwBmc" title="Freely accessible"><a class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2892770" id="mwBmg" rel="mw:ExtLink nofollow">2892770</a></span>. <a class="mw-redirect" href="./PMID_(identifier)" id="mwBmk" rel="mw:WikiLink" title="PMID (identifier)">PMID</a><span id="mwBmo" typeof="mw:Entity"> </span><a class="external text" href="https://pubmed.ncbi.nlm.nih.gov/20589188" id="mwBms" rel="mw:ExtLink nofollow">20589188</a>.</cite><span about="#mwt32" class="Z3988" id="mwBmw" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.jtitle=ResearchGate&amp;rft.atitle=The+Yellow+Fever+Vaccine%3A+A+History&amp;rft.volume=83&amp;rft.issue=2&amp;rft.pages=77-85&amp;rft.date=2010-06&amp;rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC2892770%23id-name%3DPMC&amp;rft_id=info%3Apmid%2F20589188&amp;rft.aulast=Frierson&amp;rft.aufirst=J.&amp;rft_id=https%3A%2F%2Fwww.researchgate.net%2Fpublication%2F44853136&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AApril+28"></span></span>