Photo-heliographic results 1874 to 1885 being supplementary results from photographs of the sun taken at Greenwich, at Harvard college, U.S.A., at Melbourne, in India, and in Mauritius in the years 1874 to 1885 : and measured and reduced at the Royal Observatory, Greenwich /
Royal Observatory, Greenwich.
Christie, William Henry Mahoney,1845-1922.
Edinburgh : Printed for H.M.S.O. by Neill & Co.,
1907.
Appendix to the Greenwich observations, 1905.
Sunspots.
Also available as an electronic resource via the Internet.