Спостерігачі

• 

  Andres Loton

  https://zeromio.com/%EC%98%A8%EB%9D%BC%EC%9D%B8-%EC%8A%AC%EB%A1%AF%EB%A8%B8%EC%8B%A0-%EB%A7%A4%EB%A0%A5%EA%B3%BC-%EC%A0%84%EB%9E%B5%EC%9D%98-%EC%84%B8%EA%B3%84/