Observerare

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  Ralf Dunham

  https://volvi.us/%EC%9E%90%EB%8F%99%EC%B0%A8%EB%8B%B4%EB%B3%B4%EB%8C%80%EC%B6%9C-%EC%B5%9C%EC%8B%A0%EC%A0%95%EB%B3%B4-%ED%9A%A8%EC%9C%A8%EC%A0%81%EC%9D%B8-%EC%9E%90%EA%B8%88-%EC%A1%B0%EB%8B%AC-%EB%B0%A9%EB%B2%95/