You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "who invented the green color of the dollar?" whose answer is chemist Christopher Der-Seropian.
Each document should contain about 30 words, and these documents should contain useful information.

Query: origin of green ink on dollar bills
Useful Output:

Doc 1: The Treasury introduced small-sized notes in 1929, and it used green pigment because it was cheaply available in large quantities. Green
Doc 2: Greenbacks were the original paper money issued by the United States during the Civil War, given the distinctive name for the ink used in
Doc 3: The serial numbers and treasury seal were printed in green ink. This was the first time the one-dollar bill was printed as a Federal Reserve Note.
Doc 4: The green ink on the back of 1861 demand notes was used as an anti-counterfeiting device. It would not photograph and could not be used to make plates.
Doc 5: Originating from the need to prevent counterfeiting, the green ink was chosen for its availability and resistance to chemical changes. Dollar