1. Hsü, K. J., Cita, M. B. & Ryan, W. B. F. Initial Reports of the Deep Sea Drilling Project, U.S. Government Printing Office, Washington, D.C., 13, 1203–1231 (1973).
2. Hsü, K. J., Ryan, W. B. F. & Cita, M. B. Nature 242, 240–244 (1973).
3. Hsü, K. J. et al. Initial Reports of the Deep Sea Drilling Project, U. S. Government Printing Office (in the press).
4. Ruggieri, G. Systematics Assoc. Publ. No. 7 (eds Adams, C. G. & Ager, D. V.) 283–290 (London, 1967).
5. Ryan, W. B. F. et al. Riv. Ital. Paleont. 80, 631–687 (1974).