21
Published: 1957
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 111
22
Published: 1961
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 179
23
Published: 1955
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 71
24
Published: 1960
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 163
25
Published: 1954
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 56
26
Published: [1954]
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 62
27
Published: 1953
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 48
28
Published: 1936
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 119
29
Published: 1940
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 196
30
Published: 1950
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 35
31
Published: 1937
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series I 135
32
33
Published: 1953
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 47
34
Published: 1956
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 99
35
Published: 1959
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 152
36
Published: 1954
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 67
37
Published: 1957
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 108
38
Published: 1956
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 80
39
Published: 1962
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 193
40
Published: 1957
Superior document: Reprints / The Astronomical Observatory of Harvard College : Series II 96