1. Popp, M. Science 218, 1280–1285 (1982).
2. Gabor, D., Columbo, U., King, A. & Galli, R. Beyond the Age of Waste (Pergamon, New York, 1978).
3. Fyfe, W.S. Science 213, 105–110 (1981).
4. Hill, D. et al. Science 218, 859–864 (1982).
5. Cowan, G.A., Bryant, E.A., Daniels, W.R. & Maeck, W.J. The Oklo Phenomenon (I.A.E.A., Vienna, 1975).