1
Published: 1879
Superior document: Observations de Poulkova : Suppléments 9
2
Published: 1929
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 56
3
Published: 1929
Superior document: Publications of the Yerkes Observatory 7,1
4
Published: 1932
Superior document: Publications of the Yerkes Observatory 7,2