Som et al. (2016)

Also: Som et al. 2016

Earth's air pressure 2.7 billion years ago constrained to less than half of modern levels

Som, S.M., Buick, R., Hagadorn, J.W., Blake, T.S., Perreault, J.M., Harnmeijer, J.Jelte P. & Catling, D.C. (2016). Earth's air pressure 2.7 billion years ago constrained to less than half of modern levels. Nature Geoscience. 9(6),448-451. Article

https://doi.org/10.1038/ngeo2713

References