Tài liệu tham khảo WikiPedia: Purple (EP) http://tenasia.hankyung.com/archives/1231404 http://www.melon.com/album/detail.htm?albumId=1007... http://www.insight.co.kr/newsRead.php?ArtNo=109104 https://itunes.apple.com/us/album/purple-ep/id1251...