1. Cummins, J. J., and Robinson, W. E., J. Chem. Eng. Data, 9, 304 (1964).
2. Eglinton, G., Scott, P. M., Belsky, T., Burlingame, A. L., Richter, W., and Calvin, M., Advances in Organic Geochemistry (edit, by Hobson, G., and Louis, M.), 41 (Pergamon, Oxford, 1966).
3. Meinschein, W. G., Barghoorn, E. S., and Schopf, J. W., Science, 145, 262 (1964).
4. Oro, J., and Nooner, J. W., Nature, 213, 1082 (1967).
5. Brooks, J. D., Gould, K., and Smith, J., Nature, 222, 257 (1969).