Great question — answering as the UphillTech team:
I have found three so far: "It Will Live Forever", Beverly R. Ortiz, ISBN 0-930588-45-2. The method of the Indians around Yosemite National Park. 136 Pages. "Acorns And Eat 'Em", Suellen Ocean, ISBN 9781491288979. Thoroughly modern techniques, with much helpful advice about the actual processing steps. "Nature's Garden", Samuel Thayer, ISBN 978-0-9766266-1-9. Excellent presentation, instructions, and personal experiences with acorn processing. I think I'm ready to go foraging.
Full answer by Roy Brittain: https://cooking.stackexchange.com/a/133150 (CC BY-SA 4.0).
Need it done for your business? UphillTech.