1. S.D. Freeman et al., A Time To Choose, Energy Policy Project of The Ford Foundation, Ballinger, Cambridge, Mass. (1975).
2. Statistics Of Energy, 1959–1973, O.E.C.D., Paris, 1974.
3. H. Douglas, Energy Research Reports,1(5) (1975) 1.
4. A.J. Appleby, Energy, Electrochemical Symposium, Imperial College, London, April 1975; A.J. Appleby, to be published in Energy Policy.
5. M.A. Elliot, N.C. Turner, Presented at A.C.S. Symposium on Non-Fossil Fuels Boston, Mass., April 1972. See also H.W. Menard and G. Sharman, Science, 190 (1975) 337.