Grayson, J. H. (2016). “Son Chint’ae and the Foundations of Modern Korean Folklore Studies”. 《Folklore》 129 (1): 1–17. doi:10.1080/0015587X.2017.1388020. "The term 靑丘 (Kor. Ch’ŏnggu) meaning ‘green hills’ is a historic, poetic reference to Korea...The phrase was used by the Chinese in ancient times to refer to Korea. A Chinese legend states that a meteor called Ch’ŏnggu fell to earth on the Korean peninsula. The character ch’ŏng represents the direction ‘east’ and the character ku/gu means ‘earth’ or ‘land’."
