https://www.youtube.com/watch?v=3440WFYWJhY&t=2shttp://oppaya.net/bbs/board.php?bo_table=humor&wr_id=839364 514
벌크업을 해야하는 이유
https://www.youtube.com/watch?v=3440WFYWJhY&t=2s
http://oppaya.net/bbs/board.php?bo_table=humor&wr_id=839364