[30] King, Mt. W. Contr. 53, 1911; ibid., 60, 1912.
[31] St. John and Babcock, Ap. J., 60, 32, 1924.
[32] Zeemann, Researches in Magneto-Optics, 1911.
[33] Hale, Mt. W. Contr. 30, 1908.
[34] Landé, Zeit. f. Phys., 15, 189, 1923.
[35] Stark, Elektrische Spektralanalyse Chemischer Atome, 1914.
[36] Merton, Proc. Roy. Soc., 92A, 322, 1915; ibid., 95A, 33, 1919.
[37] Anderson, Mt. W. Contr. 134, 1917.
[38] Takamine, Mt. W. Contr. 169, 1919.
[39] Evershed, Observatory, 45, 166, 1922; ibid., 45, 296, 1922.