APA (7th ed.) Citation

United States Naval Observatory. (1878). Instructions for observing transit of Mercury, 1878, May 5-6. GPO.

Chicago Style (17th ed.) Citation

United States Naval Observatory. Instructions for Observing Transit of Mercury, 1878, May 5-6. [Washington]: GPO, 1878.

MLA (9th ed.) Citation

United States Naval Observatory. Instructions for Observing Transit of Mercury, 1878, May 5-6. GPO, 1878.