Hermann Snellen
... that the Snellen eye chart developed by Hermann Snellen in 1862 is the top-selling poster in U.S. history?
... that the <a href="./Snellen_chart" id="mwEB4" rel="mw:WikiLink" title="Snellen chart">Snellen eye chart</a> <i id="mwEB8">(pictured)</i> developed by <b id="mwECA"><a class="mw-redirect" href="./Hermann_Snellen" id="mwECE" rel="mw:WikiLink" title="Hermann Snellen">Hermann Snellen</a></b> in 1862 is the top-selling poster in U.S. history?