This calculator provides a best estimate of the expiration date of a utility, plant, or design patent, based on a comprehensive list of factors than can be found in USPTO records. Download Calculator
Before relying on an expiration date, individuals should always carefully inspect all relevant documents available through the USPTO, court records and elsewhere, and consult with an attorney.
https://ptrca.org/handoutsPatent and Trademark Resource Center Association "Handout Central"
Patents Guide by Mike White. Queens University, Ontario.
End-User Patent Searching Using Open Access Sources by Pat LaCourse. Engineering and Science Librarian. New York State College of Ceramics.
Patents Guide: "Help for Researchers". British Library
"Patents, Copyrights, & Trademarks" , by National Paralegal College. Extensive guide; made for a college audience but recommended to us by a teacher of advanced middle school students.
The STEM Library is the College Park Patent & Trademark Resource Center
STEM Library (formerly known as EPSL - Engineering & Physical Sciences Library) was designated a Patent Depository Library by USPTO in January 1984. It was renamed a Patent & Trademark Depository Library in 1990, and then a PTRC in October 2011
The U.S. Government grants a patent to an inventor "to exclude others from making, using, offering for sale, or selling the invention throughout the United States or importing the invention into the United States." A trademark is a word, phrase, symbol or design, or combination of words, phrases, symbols or designs, which identifies the source of goods or services of one party from those of another. A copyright protects works of authorship, such as writings, music, and works of art that have been tangibly expressed. See: www.uspto.gov/trademarks-getting-started/trademark-basics/trademark-patent-or-copyright