1. Kistler, S. S. Nature 127, 741 (1931).
2. Fricke, J. Scient. Am. 256, 68–73 (1988).
3. Canham, L. T. Appl. Phys. Lett. 57, 1046–1048 (1990).
4. Brinker, C. J. & Scherer, G. W. Sol Gel Science Ch. 8 (Academic, San Diego, 1990).
5. Schneider, G. M. Stahl, E. & Wilcke, G. (eds) Extraction with Supercritical Gases (Verlag Chemie, Weinheim, 1980).