https://blog.naver.com/cbg6218/222637507111
https://www.joongang.co.kr/article/2697188#home
이청득심(以聽得心) - 聽(청.Listening.心.知慧)^ 聞(문.Hearing.耳.知識) - 구시화지문(口是禍之門) ^ 설시참신도(舌是斬身刀) (tistory.com)
https://blog.naver.com/cbg6218/222638979436