1. For more extensive discussion of the constituent quark model, together with a more complete set of references than can be given here, the reader is referred to the reviews by H.J. Lipkin (Phys. Reports C8 (1973)). J. Rosner (Physics Reports C11 (1974) and J. Weyers, Lectures at 1973 Louvain Summer School.
2. We are thus tacitly assuming ‘hidden’ colour for the quarks.
3. P.J. Litchfield, Review talk at the London Conference (17th Int. Conf. on High Energy Physics, London 1974, ed. J.R, Smith).
4. R.J. Hemingway, Talk at the Argonne Summer Symposium on “New Directions in Hadron Spectroscopy”, July 1975; and P. Lamb private communication.
5. O.W. Greenberg, Phys. Rev. Letts 13 (1964) 598; R.H. Dalitz, Les Houches Lectures 1965 p. 253 (Gordon and Breach, New York, 1965).