Zeebe, R. E., Dickens, G. R., Ridgwell, A., Sluijs, A., & Thomas, E. (2014). Onset of carbon isotope excursion at the Paleocene-Eocene thermal maximum took millennia, not 13 years. National Academy of Sciences.

Zeebe, Richard E., Gerald R. Dickens, Andy Ridgwell, Appy Sluijs, and Ellen Thomas. Onset of Carbon Isotope Excursion At the Paleocene-Eocene Thermal Maximum Took Millennia, Not 13 Years. National Academy of Sciences, 2014.

Zeebe, Richard E., et al. Onset of Carbon Isotope Excursion At the Paleocene-Eocene Thermal Maximum Took Millennia, Not 13 Years. National Academy of Sciences, 2014.