Executive Jackson Desk

My father purchased this desk and used it as his executive office desk for years. After his death, I have stored and cared for the desk, and am wondering if anyone knows about it's history or value. The desk is solid wood (oak) and stamped inside the drawer as a "Jackson Desk: Built like a stone wall." It was made by the Jasper furniture company. The desk has 6 regular sized drawers, one file size drawer and one wide drawer in the middle. There are also two pullout writing surfaces, one on each side. Each of the four legs has it's own leveling foot.

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