1
2
منشور في: 1951
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 38
3
منشور في: 1937
Superior document: Annals of the Astronomical Observatory of Harvard College 89,10
4
5
منشور في: 1959
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 158
6
منشور في: 1945
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 273
7
منشور في: 1945
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 274
8
منشور في: 1934
Superior document: Annals of the Astronomical Observatory of Harvard College 89,4
9
منشور في: 1950
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 35
10
منشور في: 1946
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 282
11
منشور في: 1953
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 47
12
منشور في: 1960
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 161
13
منشور في: 1954
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 67
14
منشور في: 1957
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 108
15
منشور في: 1956
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 80