1
Cyhoeddwyd: 1943
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 253
2
Cyhoeddwyd: 1946
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 286
3
Cyhoeddwyd: 1961
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 171
4
5
6
Cyhoeddwyd: 1962
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 186
7
Cyhoeddwyd: 1962
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 189
8
Cyhoeddwyd: 1958
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 132
9
Cyhoeddwyd: 1956
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 91
10
Cyhoeddwyd: 1944
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 265
11
Cyhoeddwyd: 1961
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 173
12
13
Cyhoeddwyd: 1945
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 9
14
Cyhoeddwyd: 1944
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 268
15
Cyhoeddwyd: 1953
Superior document: Annals of the astronomical observatory of Harvard College 113,2
16
Cyhoeddwyd: 1954
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 60/61
17
Cyhoeddwyd: 1955
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 77/78
18
Cyhoeddwyd: 1937
Superior document: Annals of the Astronomical Observatory of Harvard College 89,9
19
Cyhoeddwyd: 1947
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 293
20
Cyhoeddwyd: 1939
Superior document: Annals of the astronomical observatory of Harvard College 108,1