1. Possible Triple-Scattering Experiments
2. This problem is proposed in A. De Rújula and E. De Rafael, Positivity restrictions on nucleon Compton amplitudes, preprint of I.H.E.S., 91-Bures-sur-Yvette, France, to be published.
3. M.G. Doncel, L. Michel and P. Minnaert, Polarization density matrix, issues 1, 2, 3, preprints P.T.B 35, 37, 44 of Laboratoire de Physique Theorique, Université de Bordeaux I, 33-Gradignan, France (cf. especially the version of Appendix I A 3 in issue 3)
4. Matrices densité de polarisation;Salmeron,1970
5. M.G. Doncel, P. Mery, L. Michel, P. Minnaert and K.C. Wali, Properties of polarization density matrix in Regge pole models, preprint of I.H.E.S., 91-Bures-sur-Yvette, France, to be published.