Title: Premier League.
Question: When was the first year that clubs threatened to leave the Football League?

Title: Oklahoma.
Question: What caused Oklahoma's temperature to plummet 66 degrees on Nov 11, 1911?

Title: Friedrich Hayek.
Question: What other notable figure signed the letter in which Hayek made his statement regarding private investment?

Title: Gramophone record.
Question:
What material were most mailed records made of?