The spectroscopic orbit of the Cepheid variable X Cygni
By: by John C. Duncan ...
Series: Contributions from the Mount Wilson Observatory.; no. 196
Published: 1921
Place of publication: [Chicago
Language: eng
Subjects: Variable stars.
Notes: Cover-title.
At head of title: Carnegie Institution of Washington.
"Reprinted from the Astrophysical Journal, vol. LII, 1921."