The image of the stamp in Expalanation is from Wikimedia Commons is in public domain https://commons.wikimedia.org/wiki/File:Constitution_Sesquicentennial_1…
For more information about the Constitutional Convention see the following links
Wikipedia: https://en.wikipedia.org/wiki/Constitutional_Convention_(United_States)…;
Office of the Historian of USA: https://history.state.gov/milestones/1784-1800/convention-and-ratificat…
For more information about the American Revolution:
From Wikipedia:
https://en.wikipedia.org/wiki/American_Revolutionary_War
https://en.wikipedia.org/wiki/Timeline_of_the_American_Revolution
From Britannica: