Albert Schweitzer, Etching by Arthur William Heintzelman.
<bdi><a href="https://www.wikidata.org/wiki/Q29364862" class="extiw" title="d:Q29364862"><span title="artist, printmaker, and curator (1891-1965)">Arthur William Heintzelman</span></a>
</bdi>
The Library od Congress Prints &amp; Photographs Online Catalog; <a rel="nofollow" class="external free" href="https://www.loc.gov/rr/print/catalog.html">https://www.loc.gov/rr/print/catalog.html</a>