Changes

The US patent system allows for inventors, patent attorneys, and USPTO patent examiners to reference other patents that are considered prior art or related inventions. These references are theoretically in place to limit or help define the scope of a patent's claims. Often times, the patent improves upon these referenced patents or may be a new application of previously patented subject matter. Citations are also occassionally occasionally unrelated to the patent's subject matter, and therefore, cannot be fully relied upon in studies of innovation. <ref name="IEEE" />