title: How to get the sheet name from a cell when using a function such as SUM or ArrayFormula?
body: <p>I have the following formula:</p>
  
  <pre><code>=ArrayFormula(SUM(Morten!$M4:$M400))
  </code></pre>
  
  <p>How can I replace <code>Morten</code> with the contents of a cell, ie cell <code>C13</code>, so that <code>ArrayFormula</code> will still work?</p>