Reference Source #17
Public Domain
This work is in the public domain in the United States because it is a work
of the United States Federal Government under the terms of Title 17, Chapter 1,
Section 105 of the US Code.
Note: This only applies to works of the Federal Government and not to the work of
any individual U.S. state, territory, commonwealth, county, municipality, or any other
subdivision. This template also does not apply to postage stamp designs published by the
United States Postal Service since 1978.
(See 206.02(b) of Compendium II: Copyright Office Practices)