I found them at an estate sale. I didn't pay more than a quarter for each of these, and there are more where they came from. I couldn't leave without buying up almost all of the paperwork. They were even selling the lady's framed pictures of her cats and grandchildren. They didn't even take the photos out! So I wanted to give some of her stuff a good home.
And I used to work in a museum, so I'm a packrat and know how to properly preserve objects and documents.