APA (7th ed.) Citation

Rigge, W. F. (1911). The Observatory. [s.n].

Chicago Style (17th ed.) Citation

Rigge, William F. The Observatory. [s.l]: [s.n], 1911.

MLA (9th ed.) Citation

Rigge, William F. The Observatory. [s.n], 1911.

Warning: These citations may not always be 100% accurate.