1. P. Jordan, “Die Lichtquanten hypothese,”Erg. der Exakt. Naturw., 1928,17, 158.
2. P. Jordan,Zeits. f. Phys., 1935,93, 464; 1936,98, 709 and 759; 1936,99, 109.
3. L. de Broglie,C.R., 1932,195, 536, 577, 862; 1933,197, 1377; 1934,198, 135; 1934,199, 445, 1165. A coherent representation is to be found in his bookUne Nouvelle Conception de la Lumiere (181, Act. Sci. et Ind.). Further L. de Broglie and J. Winter,C.R., 1934,199, 813.
4. R. de L. Kronig,Physica, 1935,2, 491, 854, 968.
5. M. Born,Proc. Roy. Soc., (A), 1934,143, 410.