1
Έκδοση: 1943
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 253
2
Έκδοση: 1946
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 286
3
4
5
6
Έκδοση: 1962
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 186
7
Έκδοση: 1962
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 189
8
Έκδοση: 1958
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 132
9
Έκδοση: 1956
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 91
10
Έκδοση: 1944
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 265
11
Έκδοση: 1961
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 173
12
13
Έκδοση: 1945
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 9
14
Έκδοση: 1944
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 268
15
Έκδοση: 1953
Superior document: Annals of the astronomical observatory of Harvard College 113,2
16
Έκδοση: 1954
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 60/61
17
Έκδοση: 1955
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 77/78
18
Έκδοση: 1937
Superior document: Annals of the Astronomical Observatory of Harvard College 89,9
19
Έκδοση: 1947
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 293
20
Έκδοση: 1939
Superior document: Annals of the astronomical observatory of Harvard College 108,1