“…This can be easily proved either using the projection operators technique (see, for instance, the paper [18] for the treatment of a similar situation) or applying the even simpler procedure of [ 191. Furthermore, the reduced matrix elements involving s-like excitons, the momentum operator P and the final p-like excitons are the same regardless of the nature of the final state, as can be easily verified by carrying out the decomposition of the final states and using Table 1 Notice the detailed information contained in (14) with respect to the less stringent expression 4 4 cc a14e1, e2) + a,E(e1, e2) + %Tl(% e,) + a,T*(e,, e,) 9 [5] and experimentally in [ 5 ] , is clearly violated by Matsuoka's experiments.…”