Ad for <a href="https://en.wikipedia.org/wiki/Encyclopaedia_Britannica" class="extiw" title="en:Encyclopaedia Britannica">Encyclopædia Britannica</a> (11th edition, 1911) published May 1913 in <a href="https://en.wikipedia.org/wiki/National_Geographic" class="extiw" title="en:National Geographic">National Geographic</a>.
Encyclopædia Britannica
scanned by <a href="//commons.wikimedia.org/wiki/User:Infrogmation" title="User:Infrogmation">Infrogmation</a>, published on en WP