title: Structured reference lookup using the value of another cell
body: <p>The following works great:
  <code>=LOOKUP(A9,People[Name],People[Age])</code>
  Where A9 holds the name of the person I'm looking up.  This returns their age, no problem.</p>
  
  <p>Here's what I want to do:
  <code>=LOOKUP(A9,Items[Name],Items[D4])</code>
  Where D4 holds the title of the column I am looking up in the table.  So if D4 held the word "Age" it would collect the person's age.</p>
  
  <p>How do I go about doing that?
  Thank you!</p>