1925-30

Monthly Notices of the Royal Astronomical Society, Vol. 85, p.865, 1925: "The motions and the distances of spiral nebulae"

Contr from the Mount Wilson Observatory, vol. 308, pp.1-5, 1926: "Internal motions of Messier 31"

Publ of the American Astronomical Society, vol 5, p.16, 1927: "On the Accuracy With Which Parallaxes can be Determined From Spectral Class and Proper Motion"

Publ of the American Astronomical Society, vol 5, p.18, 1927; "The Parallaxes of the First Magnitude Stars"

Popular Astronomy, Vol. 38, p.26, 1930: "Are the globular clusters and the anagalactic nebulae related? (abstract)"

Popular Astronomy, Vol. 38, p.27, 1930: " A new general catalogue of nebulae (abstract)"

Publ of the Astronomical Society of the Pacific, Vol. 42, No. 245, p.23, 1930: " Are the Globular Clusters and the Anagalactic Nebulae Related?"

Publ of the Astronomical Society of the Pacific, Vol. 42, No. 245, p.31, 1930: "A New General Catalogue of Nebulae"