Note 20 — PART II. STATISTICAL STUDY OF EXTRA-GALACTIC NEBULAE
Reading edition
Pease, Mt. Wilson Comm., No. 51; Proceedings of the National Academy of Sciences, 4, 21, 1918.
Reading edition
Pease, Mt. Wilson Comm., No. 51; Proceedings of the National Academy of Sciences, 4, 21, 1918.