This wikipedia website has a brief and interesting history of stamps that are still sometimes used in lieu of signatures. I looked for the website because it pairs well with a book called, "The Name Jar." It is a story about a young Korean girl who moves to the U.S.A. carrying a name stamp - seal - that her grandmother gave her with her Korean name on it. This wikipedia website is still in need of citations for verifications, so I also thought it would be a good addition to this forum, where it may come in contact with people who can provide those citations.
https://en.wikipedia.org/wiki/Seal_(East_Asia)
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