Raymond T. Birge

Rev. Mod. Phys. 13, 233 (1941) - Published 1 October, 1941

Bruno Rossi and Kenneth Greisen

Rev. Mod. Phys. 13, 240 (1941) - Published 1 October, 1941

R. W. Ditchburn and J. C. Gilmour

Rev. Mod. Phys. 13, 310 (1941) - Published 1 October, 1941