title: How to reference Microsoft.Office.Interop.Excel dll?
body: <p>I had developed a system that deals with excel sheets in 2006 using MS VS 2005. Now, I can not  use the same reference with MS VS 2012.</p>
  
  <pre><code>var app = new Microsoft.Office.Interop.Excel.Application();
  Workbooks wbs = app.Workbooks;
  </code></pre>