[3] Monthly Notices R. A. S., 1919, 80, 104.

[4] Monthly Notices R. A. S., 1917, 77, 379.

[5] Astro-Physical Journal, 1917, 46, 249. Journ. Brit. Astron. Assoc., 1920, 30, 276.

[6] Monthly Notices, R. A. S., 1917, 77, 377.

[7] Amer. Journ. Sci., 34, 333.

[8] Monthly Notices, R. A. S., 1920, 80, 628.

[9] The Observatory 1920, April. From an Oxford Note Book.

[10] Monthly Notices, R. A. S., 1917. 78, 3 De Sitter, 1919, 80, 121, Jeans, 80, 146 Jeffreys.

[11] “Gravitation and the Principle of Relativity,” Eddington. Royal Institution of Great Britain, 1918.

[12] Journ. Brit. Astron. Assoc., 1920, 30, 125.