1. R.P. Feynman: in QED, The Strange Theory of Light and Matter, Princeton University Press (1985)
2. P.A.M. Dirac: Scientific American 208, 45 (1963)
3. Attention is drawn, however, to A. Rich’s contribution to this symposium regarding a discrepancy between QED theory and experiment for the positronium decay rate
4. L.Kay: Nuci. Instr. & Meths. B9 544 (1985), and S. Bashkin, Nucl.Instr. & Meths. B9 546 (1985)
5. I.A. Sel l in et al, Phys Lett A61 107 (1977)