Observadores

• 

  Erma Baier

  https://gridsectoring.com/%ED%8C%8C%EC%9B%8C%EB%B3%BC%EC%98%88%EC%B8%A1%EC%82%AC%EC%9D%B4%ED%8A%B8-%ED%99%9C%EC%9A%A9%EB%B2%95%EA%B3%BC-%EA%B7%B8-%EC%A4%91%EC%9A%94%EC%84%B1/