Antique movie advertising posters li

The posters state in fine print at the bottom that they are property of the National Screen Service Corp. and must be returned or destroyed after use, all are numbered. I have Star Wars, the Godfather, Tom Thumb, White maybe, and Libel posters along with a few others. I have no idea what they are worth not much else about them but I'm very interested in what they're worth. Any help is highly appreciated, thank you.

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