[O] showing standard references (e.g. column B) in tables using C-c }

[Stephen Eglen]

When using C-c } in a table, the columns are labelled $1, $2, etc.  How
can I get them labelled as "A", "B" etc, as in the figure 

http://orgmode.org/worg/images/bzg/reference_visualization.jpg

Thanks, Stephen