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https://askliterature.com/poetry/critical-analysis-of-sylvia-plaths-ariel/#:~:text=Critical%20Analysis%20of%20%E2%80%9CAriel%E2%80%9D%2C%20shows%20that%20like%20other,was%20also%20recorded%20for%20BBC%20ten%20days%20later.

Wikipedia: Ariel (poetry collection)