My great grandmother Lizzie M. Adams sold her patent (number 680,106) to C. H. Munson in the early 1900s, I think. I have a newspaper article of the sale but no date.
I'm trying to work out how many virtual reality patents are assigned each year, and how the size of the market has changed. I also want to work out how many patents are reassigned each year, and how ...
When I researched the assignment history of a patent I found one assignment (from assignor A to assignee B) and a later assignment (from assignor B and C to assignee D). Where does C come from?