title: How to reference a cell where sheet name is cited as a value from a different workbook?
body: <p>I have two workbooks <code>data.xlsx</code> (which is a readonly and contains sheets <code>mainsheet</code>, <code>a</code>, <code>b,</code>c<code>,</code>d<code>...) and</code>result.xlsx` (where I will put all my computations and formula).</p>
  
  <p><code>data.xlsx!mainsheet</code> contains:</p>
  
  <pre>
  -------
  A | B |
  -------
  1 | c |
  2 | b |
  3 | a | 
  .
  .
  .
  -------
  </pre>
  
  <p>and <code>results.xlsx</code> contains </p>
  
  <pre>
  -------------------
    | A  |  B |  C  |
  -------------------
  1 |S1  | S2 | Sum |
  2 | 3  |  1 |     |
  3 | 2  |  3 |     |
  4 | 1  |  2 |     | 
  </pre>
  
  <p>Values of cell <code>A1</code> of sheets <code>a</code>, <code>b</code>, <code>c</code> are 10, 5 and 50 respectively.</p>
  
  <p><strong>What should be the formula so that:</strong></p>
  
  <p>Sheet C2 should be the sum of A1 values of sheet a and c</p>
  
  <p>Sheet C3 should be the sum of A1 values of sheet b and a</p>
  
  <p>Sheet C2 should be the sum of A1 values of sheet c and b </p>
  
  <p>So the expected result will be cell C2 = 10+50=60, C3=5+10=15, C4=50+5=55.</p>