how to automate a report based in several Workbooks
 

Hi,

i'm trying to workout this problem:

I have a workbook that contains data from several workbooks. Each original workbook have data from a particulary month, and every month i have to agregate data from the last 3 month.

Like this, the July report has to have data from June and May. In August, from June and July etc etc.

How can i automate this, just to avoid editing links and formulas every month?

Thanks