[14] The Observatory, September, 1906.
[15] Nature, March 1, 1900.
[16] Cycle of Celestial Objects, p. 96.
[17] Ast. Nach. No. 3737.
[18] Observatory, September, 1906.
[19] Nature, November 29 and December 20, 1894.
[20] Bulletin, Ast. Soc. de France, July, 1898.
[21] Observatory, vol. 8 (1885), pp. 306-7.
[22] Nature, October 30, 1902.
[23] Charles Lane Poor, The Solar System, p. 170.