Professional Football Researchers Association Forum

I've went through our Gamebooks, which were helpful, but still missing a lot of data on the defensive side. I have seen several media guides from even as early as 1969 (Dolphins, Bears, and Colts) that have tracked individual defensive stats, e.g. tackles, tfl, sacks, ff, qb hurries and state "Unofficial Press Box Statistics" as a disclaimer. So I'm hoping to locate some of those records.

Any leads on where to look or if you have any of these sources that would be great. TYIA!!