1. Hubbard, W. B. et al. Nature 336, 453–454 (1988).
2. Elliot, J. L. et al. Icarus, 77, 148–170 (1989).
3. Sykes, M. V., et al. Science 237, 1336–1340 (1987).
4. Lunine, J. I., Atreya, S. K. & Pollack, J. B. in Origin and Evolution of Planetary and Satellite Atmospheres (eds Atreya, S. K., Pollack, J. B. & Matthews, M. S.) 605–665 (University of Arizona Press, in the press).
5. Buie, M. W. & Fink, U. Icarus 70, 483–498 (1987).