<p>Photograph of early <a href="https://en.wikipedia.org/wiki/American_football" class="extiw" title="w:American football">American football</a> player and coach <a href="https://en.wikipedia.org/wiki/Percy_Haughton" class="extiw" title="w:Percy Haughton">Percy Haughton</a> from 
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<cite class="book" style="font-style:normal"><a href="//commons.wikimedia.org/wiki/Charles_Dudley_Daly" title="Charles Dudley Daly"> Daly, Charles Dudley</a> (1921)      <i> American Football</i>, <a href="https://en.wikipedia.org/wiki/en:Category:New_York" class="extiw" title="w:en:Category:New York"><span title="Wikimedia category">Category:New York</span></a>:  <a href="//commons.wikimedia.org/w/index.php?title=Harper_%26_Brothers&amp;action=edit&amp;redlink=1" class="new" title="Harper &amp; Brothers (page does not exist)">Harper</a>, pp. 101  <small></small></cite> <a rel="nofollow" class="external text" href="http://www.worldcat.org/oclc/1445510">OCLC 1445510</a>.
Unknown author<span style="display: none;">Unknown author</span>
<a href="https://en.wikipedia.org/wiki/1919" class="extiw" title="w:1919">1919</a>
Google Books <a rel="nofollow" class="external free" href="https://books.google.com/books?id=x2pLAAAAMAAJ&amp;pg=PA101-IA2&amp;source=gbs_selected_pages&amp;cad=0_1">https://books.google.com/books?id=x2pLAAAAMAAJ&amp;pg=PA101-IA2&amp;source=gbs_selected_pages&amp;cad=0_1</a> , also at Internet Archive <a rel="nofollow" class="external free" href="https://archive.org/details/americanfootball00dalyiala">https://archive.org/details/americanfootball00dalyiala</a>