http://www.uspto.gov/web/offices/pac/mpep/s2701.html "Archived copy" term of a patent term of a patent "Archived copy" "Archived copy" "Archived copy" https://www.uspto.gov/web/offices/pac/mpep/s2701.html "Archived copy" twenty years. "Archived copy" term of a patent http://www.uspto.gov/web/offices/pac/mpep/s2701.html United States Patent and Trademark Office: 2701 Patent Term