1. BhabhaCurrent Science, 1945,14, 89–90, referred to here asA.
2. Bhabha In course of publication in theRev. of Mod. Phys., 1945, referred to here asB.
3. DiracProc. Roy. Soc., A, 1936,155, 447–459.
4. FierzHelv. Phys. Acta, 1939,12, 3–37.
5. Fierz and PauliProc. Roy. Soc., A, 1939,173, 211–32.