U.S. Patent Act
..Part II. Patentabililty of Inventions and Grant of Patents
....Chapt. 13. Review of Patent and Trademark Office
When an appeal is taken to the United States Court of Appeals for the Federal Circuit, the appellant shall file in the Patent and Trademark Office a written notice of appeal directed to the Commissioner, within such time after the date of the decision from which the appeal is taken as the Commissioner prescribes, but in no case less than 60 days after that date.