1. Stommel, H. & Schott, F. Deep-Sea Res. 24, 325–329 (1977).
2. Jenkins, W. J. J. mar. Res. 38, 533–569 (1980).
3. Armi, L. & Stommel, H. J. phys. Oceanogr. (submitted).
4. Riley, G. Bull. Bingham Oceanogr. Coll. 13, 1–126 (1951).
5. Jenkins, W. J. Science 196, 291–292 (1977).