Conversation so far:
Who were some of Coopers closer friends?
Cooper's twenty-year friendship with Ernest Hemingway.
What was important about his friendship with Hemingway?
The previous year, Hemingway drew upon Cooper's image when he created the character of Robert Jordan for the novel For Whom the Bell Tolls.

Question: Which other friends did he have?
Self-contained rewrite: Besides Ernest Hemingway, which other friends did Gary Cooper have?