There is enough doubt that CBS must produce the original of this memmo. No 3rd or 5th or 30th generation copies, faxes or scans. And the original needs to be verified by a number of outside experts.
If they can not produce the original they should not have run this story.
I know you wanted a link, not my opinion. Sorry.
There is no longer any doubt. flounder has nailed it to the wall and framed it. It is now one hundred percent certain and unarguable. You cannot prove a copied document is genuine, but in this particular case you can prove absolutely that no process known to man could have produced those documents before 1981.