https://purengom.com/2008/06/13/%eb%82%98%ec%81%9c-%ec%86%8c-%ec%a6%9d%ed%9b%84%ea%b5%b0-bad-cow-disease-%ec%9d%b4%eb%aa%85%eb%b0%95%ea%b3%bc-%ea%b9%80%ec%a2%85%ed%9b%88%ec%9d%80-%ec%9d%bd%ec%9c%bc%eb%9d%bc/