Perrine, Charles D. (1923). "Contribution to the history of attempts to test the theory of relativity by means of astronomical observations". Astronomische Nachrichten. 219 (17): 281–284. Bibcode:1923AN....219..281P. doi:10.1002/asna.19232191706.
Campbell & Curtis (1914). "The Lick Observatory-Crocker Eclipse Expedition to Brovarý, Russia". Publications of the Astronomical Society of the Pacific. 26 (156): 225–237. Bibcode:1914PASP...26..225C. doi:10.1086/122351. S2CID120712519.
Perrine, Charles D. (1923). "Contribution to the history of attempts to test the theory of relativity by means of astronomical observations". Astronomische Nachrichten. 219 (17): 281–284. Bibcode:1923AN....219..281P. doi:10.1002/asna.19232191706.
Campbell & Curtis (1914). "The Lick Observatory-Crocker Eclipse Expedition to Brovarý, Russia". Publications of the Astronomical Society of the Pacific. 26 (156): 225–237. Bibcode:1914PASP...26..225C. doi:10.1086/122351. S2CID120712519.
Campbell & Curtis (1914). "The Lick Observatory-Crocker Eclipse Expedition to Brovarý, Russia". Publications of the Astronomical Society of the Pacific. 26 (156): 225–237. Bibcode:1914PASP...26..225C. doi:10.1086/122351. S2CID120712519.