1. Casagrande, D.J., 1987. Sulphur in peat and coal. in: Scott, A.C. (Ed.), Coal and Coal-bearing Strata: Recent Advances. Geological Special Publication, No. 32, London, 87–105.
2. Sulphur in peat-forming systems of Okefenokee swamp and Florida everglades: origin of sulphur in coal;Casagrande;Geochim. Cosmochim. Acta,1977
3. Chen, J., 1987. A further study on the coalification model of the Upper Permian carbonate coal measures in southern China. In: Proceedings of the Symposium on China's Permo-Carboniferous Coal-bearing Strata and Geology. Science Press, Beijing, China, pp. 217–223 (in Chinese with English abstract).
4. Chou, C.-L., 1990. Geochemistry of sulphur in coal. in: Orr, W.L., White, C.M. (Eds), Geochemistry of Sulphur in Fossil Fuels, Chap. 2. American Chemical Society Symposium Series 429, 30–52.
5. Diessel, C.F.K., 1986. On the correlation between coal facies and depositional environments. Advances in the study of the Sydney basin. Proceedings of 20th Symposium of University of Newcastle, pp. 19–22.