Biblio
. 1895. Douglass, AE_A Cloud Like Spot on the Terminator of Mars_1895.pdf (172.04 KB)
“A Photographic Periodogram Of The Sun-Spot Numbers”. The Astrophysical Journal, XL (No. 3). The Astrophysical Journal, .
. 1914. Douglass, AE_A Photographic Periodogram of the Sun-Spot Numbers_1914.pdf (7.69 MB)