1. “Native Bitumens Associated with Oil Shales”;Bell,1963
2. H., Abraham, Asphalts and Allied Substances, I, Van Nostrand, Princeton, N.J., 6th ed., pp. 56–57 (1960).
3. “Evolution and Alteration of Petroleum in Western Canada”;Evans;Chem. Geol.,1971
4. J.A., Williams and J.C., Winters, Symp. Petroleum Transformation in Geologic Environments, 158th Natl. Meet. Am. Chem. Soc., New York, N.Y. (1969).
5. “Alteration of Crude Oil by Water and Bacteria — Evidence From Geochemical and Isotope Studies”;Bailey;Bull. Am. Assoc. Pet. Geol.,1973