http://terms.naver.com/entry.nhn?cid=747&docId=67219&mobile&categoryId=2319
http://news.naver.com/main/read.nhn?mode=LSD&mid=sec&sid1=102&oid=001&aid=0006096411
http://news.naver.com/main/read.nhn?mode=LSD&mid=sec&sid1=102&oid=001&aid=0005743252
http://www.nongmin.com/article/ar_detail.htm?ar_id=210367&subMenu=articletotal
있다니까요 -_-