Osservatori

• 

  Micheal Pederson

  https://elronet.com/%EC%B9%B4%EC%A7%80%EB%85%B8%EC%B9%9C%EA%B5%AC-%EB%B0%94%EC%B9%B4%EB%9D%BC%EC%82%AC%EC%9D%B4%ED%8A%B8/