1. Maunciple, V. A., Boone, P. S. & Obispo, S. Gerontol. Res. 26, 958–967 (1989).
2. Mond, M., Marx, B. F. & Watson, H. J. devl Biol. 34, 1044–1056 (1992).
3. Kawaguchi, Y. et al. Jap. J. expl Endocrinol. 13, 1418–1427 (1993).
4. Ariellos, C., Prosperou, K. K., Kaliban, D. W., Mirander, B. P. & Kawaguchi, Y. Proc. natn. Acad. Sci. (in the press).
5. Correspondent, A. A. Nature 296, 392–393 (1982).