1. For a preliminary account see: D. Morgan, M.R. Pennington: Proc. of 3rd Int. Conf. on Hadron Spectroscopy (‘Hadron 89’), Ajaccio, Corsica, 1989, F. Binon, J.-M. Frère, J.P. Peijneux (eds), Editions Frontières, p. 291. For an exposition of the method see: M.R. Pennington, Proc. VIII Int. Workshop on photon-photon collisions, Shoresh, Israel, 1988; U. Karshon (ed.) p. 297, Singapore: World Scientific 1988
2. Mark II collaboration (to be published); J. Boyer (thesis) LBL-27180 (1989), and private communication
3. H. Marsiske et al. Crystal Ball Coll.: Phys. Rev. D41 (1990) 3324
4. H. Marsiske: Proc. VIII Int. Workshop on photon-photon collisions, Shoresh, Israel, 1988; U. Karshon (ed.) p. 15, Singapore: World Scientific 1988; H. Marsiske (Hamburg U. thesis) DESY F31-88-02 (1988), and private communication
5. A.I. Alekseev: Sov. Phys. JETP 34 (7), 826 (1958); R. Barbieri, R. Gatto, R. Kögerler: Phys. Lett. 60B (1979) 183