1. Hayes, J.M., Kaplan, I.R. and Wedeking, K.W.: Precambrian Organic Geochemistry, Preservation of the Record in J.W. Schopf (ed),Earths Earliest Biosphere, its Origin and Evolution, Princeton University Press, Princeton (1983) pp. 93?132.
2. McKirdy, D.M. and Hahn, J.H.: The Composition of Kerogen and Hydrocarbons in Precambrian Rocks in H.D. Holland and M. Schidlowski (eds.),Mineral Deposits and Evolution of the Biosphere, Springer-Verlag, Berlin, Heidelberg, New York (1982) pp. 123?154.
3. Strauss, H., Des Marais, D.J., Hayes, J.M. and Summons, R.E.: Concentrations of Organic Carbon and Maturities and Elemental Composition of Kerogens in J.W. Schopf and C. Klein (eds.),The Proteozoic Biosphere ? A Multidisciplinary Study, Cambridge University Press, Cambridge (1992) pp. 95?99.
4. ibid: Proterozoic Organic Carbon ? its Preservation and Isotopic Record in M. Schidlowski, S. Golubic, M.M. Kimberley, D.M. McKirdy and P.A. Trudinger (eds.),Early Organic Evolution ? Implications for Mineral and Energy Resources, Springer-Verlag, Berlin, Heidelberg, New York (1992) pp. 203?211.
5. Summons, R.E.: Abundance and Composition of Extractable Organic Matter in J.W. Schopf and C. Klein (eds.),The Proterozoic Biosphere ? A multidisciplinary study, Cambridge University (1992) pp. 101?115.