1. Alexander, R. McN. Nature 353, 696 (1991).
2. Beuchat, C. A. Am. J. Physiol. 258, R298–R308 (1990).
3. Goldstein, D. L. & Braun, E. J. Am. J. Physiol. 256, R501–R509 (1987).
4. Greenwald, L. Physiol. Zool. 62, 1005–1014 (1989).
5. Greenwald, L. & Stetson, D. News Physiol. Sci. 3, 46–49 (1988).