1. B. L. Cohen, “Cost per Million BTU of Solar Heat, Insulation, and Conventional Fuels,” American Journal of Physics, 52, 614 (1984).
2. R. H. Annan and J. L. Stone, “The U.S. National Photovoltaics Program- Investing in Success,” Solar Cells, 26, 135 (1989).
3. Solar Energy Research Institute, Photovoltaics Technical Information Guide (Second Edition), p. 58 (1988).
4. U.S. Department of Energy, Photovoltaic Energy Program Summary (1988).
5. U.S. Department of Energy, Solar Thermal Energy Program Summary (1988).