Retallack, G.J.; Krull, E.S.; Thackray, G.D.; Parkinson, D. (2013). "Problematic urn-shaped fossils from a Paleoproterozoic (2.2 Ga) paleosol in South Africa". Precambrian Research. 235: 71–87. Bibcode:2013PreR..235...71R. doi:10.1016/j.precamres.2013.05.015.
Schneider, D.A.; Bickford, M.E.; Cannon, W.F.; Schulz, K.J.; Hamilton, M.A. (2002). "Age of volcanic rocks and syndepositional iron formations, Marquette Range Supergroup: implications for the tectonic setting of Paleoproterozoic iron formations of the Lake Superior region". Canadian Journal of Earth Sciences. 39 (6): 999–1012. Bibcode:2002CaJES..39..999S. doi:10.1139/e02-016.
Murakami, T.; Sreenivas, B.; Sharma, S.D.; and Sugimori, H. (2011). "Quantification of atmospheric oxygen levels during the Paleoproterozoic using paleosol compositions and iron oxidation kinetics". Geochimica et Cosmochimica Acta. 75 (14): 3982–4004. Bibcode:2011GeCoA..75.3982M. doi:10.1016/j.gca.2011.04.023.
Retallack, G.J.; Krull, E.S.; Thackray, G.D.; Parkinson, D. (2013). "Problematic urn-shaped fossils from a Paleoproterozoic (2.2 Ga) paleosol in South Africa". Precambrian Research. 235: 71–87. Bibcode:2013PreR..235...71R. doi:10.1016/j.precamres.2013.05.015.
Schneider, D.A.; Bickford, M.E.; Cannon, W.F.; Schulz, K.J.; Hamilton, M.A. (2002). "Age of volcanic rocks and syndepositional iron formations, Marquette Range Supergroup: implications for the tectonic setting of Paleoproterozoic iron formations of the Lake Superior region". Canadian Journal of Earth Sciences. 39 (6): 999–1012. Bibcode:2002CaJES..39..999S. doi:10.1139/e02-016.
Murakami, T.; Sreenivas, B.; Sharma, S.D.; and Sugimori, H. (2011). "Quantification of atmospheric oxygen levels during the Paleoproterozoic using paleosol compositions and iron oxidation kinetics". Geochimica et Cosmochimica Acta. 75 (14): 3982–4004. Bibcode:2011GeCoA..75.3982M. doi:10.1016/j.gca.2011.04.023.