1
2
Έκδοση: 1955
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 68
3
Έκδοση: 1956
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 87
4
Έκδοση: 1946
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 284
5
Έκδοση: 1939
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 175
6
Έκδοση: 1945
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 275
7
Έκδοση: 1939
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 180
8
Έκδοση: 1944
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 260
9
Έκδοση: 1936
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 122
10
Έκδοση: 1952
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 42
11
Έκδοση: 1957
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 110
12
Έκδοση: 1952
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 45
13
Έκδοση: 1954
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 66
14
15
Έκδοση: 1938
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 144
16
Έκδοση: 1945
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 273
17
Έκδοση: 1945
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 274
18
Έκδοση: 1956
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 99
19
Έκδοση: 1956
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 86