minor addition

stages/draw-advanced-literature/index.html

@@ -65,6 +65,7 @@ <h2>Background</h2>
             <td>https://en.wikipedia.org/wiki/Pentose_phosphate_pathway</td>
           </tr>
             </table>
+      <p>These instructions use a <b>DOI</b> reference as an example, but the general workflow would be the same for any of the above listed reference types.</p>
 
       <h2>Challenge</h2>
 	  <p>