Dreisam. SCFreiburg. 28 June 2019 [28 June 2019]. (原始内容存档于2021-01-17) (德语). S. Korean midfielder signs with German Bundesliga club Freiburg. Yonhap News
Engelen, B., & Freiburg, C. (1979). Kristallstruktur von Mangan (II) sulfit-Trihydrat, α-MnSO3· 3H2O/Crystal Structure of Manganese (II) sulfite Trihydrate