1
Published: 1929
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 59
2
3
Published: 1928
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 54
4
Published: 1927
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 37
5
Published: 1929
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 56