1. Under the Sun, the Newsletter of LUZ International Ltd., 4 (1988)
2. Flachglas Solartechnik, private communication, Köln (D), 1987/88/89
3. SPS-Stirling Power Systems Corporation, private communication, 1987
4. Presentation Material, Ann Arbor/Ml, Stirling Power Systems Corp. (SPS), 1987/88
5. Annual Progress Report: Photovoltaics, FY 1986. DOE/CH/10093-H3, 1987