BCP 38 coverage if top x providers ...

My google fu is failing me, but I believe there was a NANOG posting a year or two ago that mentioned that if the top x providers would implement BCP 38 then y% of the traffic (or Internet) would be de-spoofed. The point was that we don't even need everyone to implement BCP 38, but if the largest (transit?) providers did it, then UDP reflection attacks could be minimized. If someone can recall the key words in that posting and dig it up, that would be much appreciated. Frank