Which of the following procedures focuses exclusively on patents and printed publications?

The choice that focuses exclusively on patents and printed publications is ex parte reexamination. This procedural mechanism allows a third party or the patent owner to request the United States Patent and Trademark Office (USPTO) to reexamine a granted patent based on the belief that one or more claims of that patent are either invalid in light of prior art, such as patents and printed publications. The process is conducted in a manner where the patent owner can participate, but it is primarily about scrutinizing the documents related to the existing patent claims.

Unlike some other procedures, ex parte reexamination is specifically designed to address issues arising from prior art references without delving into other aspects such as litigation-related challenges or more complex reviews. This makes it unique as it directly revolves around the examination of patents and printed publications for potential prior art issues.

By focusing narrowly on these sources of information, ex parte reexamination aids in maintaining the integrity of the patent system by allowing invalid claims to be modified or canceled based on previously undiscovered relevant information.