Hanʼguk ŭi Yongam tonggul
By: Hong Si-hwan.
Publisher: Taehak Sorim; Hanʼguk Tonggul Hakhoe
Published: 1982
Place of publication: [Sŏul Tʻŭkpyŏlsi]
Language: kor
Number of pages: 84
Subjects: Lava tubes -- Korea (South) -- Cheju-do; Caves -- Korea (South) -- Cheju-do