Não informado. (1911). Contributions from the Princeton University Observatory. Princeton University Observatory.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Contributions from the Princeton University Observatory. Princeton, NJ: Princeton University Observatory, 1911.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Contributions from the Princeton University Observatory. Princeton University Observatory, 1911.
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