http://www.hani.co.kr/arti/science/kistiscience/560149.html
https://namu.wiki/w/%ED%8E%A0%EB%A6%AD%EC%8A%A4%20%EB%B0%94%EC%9B%80%EA%B0%80%EB%A5%B4%ED%8A%B8%EB%84%88
http://www.hani.co.kr/arti/science/kistiscience/560149.html
https://namu.wiki/w/%ED%8E%A0%EB%A6%AD%EC%8A%A4%20%EB%B0%94%EC%9B%80%EA%B0%80%EB%A5%B4%ED%8A%B8%EB%84%88