Only I Didn't Know (Music video) on YouTube Only I Didn't Know (IU version music video) on YouTube Only I Didn't Know (Music video teaser) on YouTube IU's official website
Truy cập ngày 24 tháng 11 năm 2013.  Only I Didn't Know (Music video) trên YouTube Only I Didn't Know (IU version music video) trên YouTube Only I Didn't Know (Music video teaser) trên YouTube IU's official website