G. A. Hulett
Phys. Rev. (Series I) 27, 337 (1908) - Published 1 November, 1908
Edward L. Nichols and Ernest Merritt
Phys. Rev. (Series I) 27, 367 (1908) - Published 1 November, 1908
J. K. Robertson
Phys. Rev. (Series I) 27, 400 (1908) - Published 1 November, 1908
S. J. Barnett
Phys. Rev. (Series I) 27, 425 (1908) - Published 1 November, 1908