S. A. Korff and G. Breit

Rev. Mod. Phys. 4, 471 (1932) - Published 1 July, 1932

G. Breit

Rev. Mod. Phys. 4, 504 (1932) - Published 1 July, 1932

Philip M. Morse

Rev. Mod. Phys. 4, 577 (1932) - Published 1 July, 1932