I just found these, so maybe there’s an easier way to access them, but I haven’t found it yet. I include them here because they are good resources.
Classic Fantasy Literature: Gary Gygax’s Inspirational Reading List.
Official Fantasy RPG modules from the 1970s: Good scans of the cover art.
World of Greyhawk core.
World of Greyhawk Bibliography.
World of Midkemia.
22 questions on Tharizdun.
Wizards.com Greyhawk vault.
Lost Deities & Demigods of Greyhawk: in PDF format.