1. Chang, K.H. (1975) Cretaceous stratigraphy of Southeast Korea. Journal of the Geological Society of Korea, v.11(1), p.1-23.
2. Recent advances in the cretaceous stratigraphy of Korea
3. A new tree fern stem, Heilongjiangcaulis keshanensis gen. et sp. nov., from the Cretaceous of the Songliao Basin, Northeast China: a representative of early Cyatheaceae
4. Cheong, C.H. and Paik, K.H. (1992) Study on tree fern fossil site at Mt. Geummubong. Report on Natural Monument and Dinosaur Tracks, The Geological Society of Korea, p.3-41(in Korean).
5. Choi, S.J. (1989) Fossil charophytes from the Nagdong Formation in Seonsangun, Gyeongsangbukdo, Korea. Journal of the Paleontological Society of Korea, v.5, p.28-38.