1
Έκδοση: 1889
Superior document: Annals of the Astronomical Observatory of Harvard College 22
2
Έκδοση: 1855-1855
3
Έκδοση: 1875
4
Έκδοση: 1878
5
“...USA Army...”
6
“...USA Army Signal Corps...”
7
“...USA Army Signal Corps...”
8
Έκδοση: 1876
Links: Volltext