1. H. W. Baer, K. M. Crowe and P. Truöl, in Advances in Nuclear Physics, vol.9, M. Baranger and E. Vogt, eds. (Plenum, New York, 1977 p.177.
2. C. Tzara, in Meson-Nuclear Physics-1976, P. D. Barnes et al., eds. (American Institute of Physics, New York, 1976 p.566; P. Truöl,ibid., p.581; J. H. Koch, ibid; p.591.
3. H. W. Baer, in Proc. Seventh Int. Conf. on High-Energy Physics and Nuclear Structure, M. P. Locher, ed. Birkhäuser Verlag, Basel, 1977 p.245.
4. J. B. Perroud, in Proc. Int. Symp. on Photopion Nuclear Physics, Troy, N.Y., 1978, to be published.
5. P. Truöl, in Proc. IKO Summer Study Week, Amsterdam, 1978, to be published.