title: Excel number format strings (e.g. "@", "$-409]d-mmm-yy;@") - Complete reference availability?
body: <p>I'm using Spreadsheet Gear to do some Excel programming. I want more control over number formats and it appears that I need to use the <code>NumberFormat</code> property to achieve this.</p>
  
  <p>I've seen suggestions that you can use "<code>@</code>" to specify a string for example, but can't find a complete reference on this.</p>
  
  <p>I'm guessing it's Excel specific as opposed to Spreadsheet Gear specific.</p>
  
  <p>Can anyone help me to find a full reference, or at least a decent list?</p>