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Lichtenberger Engineering Library

Citing Sources

Citation format instruction for technical & scientific writing.

About Patents

What is a patent?

  • A monopoly is viable for approximately 20 years in the country in which the patent is issued.
  • Patent owners have the right to exclude others from making or selling the invention.
  • U.S. Patents are granted by the U.S. Patent and Trademark Office. USPTO handles over 300,000 patent applications per year. Most countries have their own intellectual property office.
  • A patent held in the U.S. only means that the rights in the U.S. are protected. Inventors must file patents in several places to get comprehensive coverage. This means that there are many, many places to find patent literature.
  • More than 8 million U.S. patents have been awarded since 1790.
  • There are 3 types of patents: Utility (91%), Design (9%), Plant (0.5%).

Why search the patent literature?

  • To identify new research fronts and/or licensing opportunities;
  • To avoid duplication of research efforts;
  • To learn how something works (diagrams, detailed description);
  • To find information on a company’s activities or to identify experts in a field;
  • To gain protection for an idea or invention; and
  • To find technical information. It is estimated that 85-90% of technical information disclosed in patents appear no place else

To learn more about patent research, go to the University of Iowa Lichtenberg Library Patent LibGuide.

How to Cite Patents

Citing a patent or a patent application varies depending on the style manual used. It is important to check with your instructor, editor or publisher to know which citation format to use.

Examples of how to cite US Patent 3,597,875 using three different style manuals:

ACS Style Guide

The minimum data required for an acceptable citation are the name(s) of the patent owner(s), the patent number, and the date. Ensure that the patent stage (Patent, Patent Application, etc.) is indicated and that the pattern of the number (e.g., spaces, commas, dashes) follows that of the original patent document. If possible, include the title and the Chemical Abstracts reference (preceded by a semicolon) as well. Patents p. 310

U.S. patent numbers are always written with commas: U.S. Patent 6,555,655. The patent numbers of other countries should be presented as on the original patent number. p. 208

Christensen, Godtfred Kirk. Toy buildings set. U.S. Patent 3,597,875, August 10, 1971.

AMA Manual of Style (10th edition) Online

3.13.7 Patents

Christensen, Godtfred Kirk, inventor; Interlego Ag, assignee. Toy building set. US patent 3,597,875. August 10, 1971.

Chicago Manual of Style

14.230 Patents Patents are cited under the names of the creators and dated by the year of filing.

15.50 Patents or other documents cited by more than one date Cite patents and other documents that include more than one date as follows (note that the year of issue is repeated to avoid ambiguity).

Christensen, Godtfred Kirk. US Patent 3,597,875 filed November 18, 1968, and issued August 10, 1971.