These are the 6 articles I wrote for the ACBL Bulletin on Doubles (in order of difficulty):
Takeout Doubles
Negative Doubles
Responsive Doubles
Support Doubles
Low Level Doubles
Lead-directing, Maximal and other Doubles
You might also consider getting Larry's book on Doubles and Redoubles HERE or try Michael's Doubles Webinar which you can find HERE.
(from the short side) on this layout: