title: Creating an Excel chart that uses data from multiple sheets
body: <p>Consider the following case:  </p>
  
  <ul>
  <li>I have a single Excel workbook with 4 sheets in it.</li>
  <li>Each sheet represents one quarter of a year.</li>
  <li>Each sheet contains 2 columns:
  <ul>
  <li>Date</li>
  <li>Revenue</li>
  </ul></li>
  </ul>
  
  <p>I now want to create a line graph for daily revenue over the whole year.<br>
  The X-axis should start at January 1st (first row of the first column of the first sheet) and end at December 31st (last row of the first column of the fourth sheet).<br>
  There should be a single line plotting the daily sales over that year on the Y-axis.</p>