Scott, Andrew C. & Rex G. 1985. The formation and significance of Carboniferous coal balls (1985). "The Formation and Significance of Carboniferous Coal Balls". Philosophical Transactions of the Royal Society. B 311 (1148): 123–137. Bibcode:1985RSPTB.311..123S. doi:10.1098/rstb.1985.0144. JSTOR2396976.
Raiswell, R. (1997). "A geochemical framework for the application of stable sulphur isotopes to fossil pyritization". Journal of the Geological Society. 154 (2): 343–356. Bibcode:1997JGSoc.154..343R. doi:10.1144/gsjgs.154.2.0343.Parameter |s2cid= yang tidak diketahui akan diabaikan (bantuan)
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Scott, Andrew C. & Rex G. 1985. The formation and significance of Carboniferous coal balls (1985). "The Formation and Significance of Carboniferous Coal Balls". Philosophical Transactions of the Royal Society. B 311 (1148): 123–137. Bibcode:1985RSPTB.311..123S. doi:10.1098/rstb.1985.0144. JSTOR2396976.
Raiswell, R. (1997). "A geochemical framework for the application of stable sulphur isotopes to fossil pyritization". Journal of the Geological Society. 154 (2): 343–356. Bibcode:1997JGSoc.154..343R. doi:10.1144/gsjgs.154.2.0343.Parameter |s2cid= yang tidak diketahui akan diabaikan (bantuan)
jstor.org
Scott, Andrew C. & Rex G. 1985. The formation and significance of Carboniferous coal balls (1985). "The Formation and Significance of Carboniferous Coal Balls". Philosophical Transactions of the Royal Society. B 311 (1148): 123–137. Bibcode:1985RSPTB.311..123S. doi:10.1098/rstb.1985.0144. JSTOR2396976.