APA (7th ed.) Citation

Young, C. A. (2011). A Textbook of General Astronomy For Colleges and Scientific Schools. Project Gutenberg.

Chicago Style (17th ed.) Citation

Young, Charles A. A Textbook of General Astronomy For Colleges and Scientific Schools. Project Gutenberg, 2011.

MLA (9th ed.) Citation

Young, Charles A. A Textbook of General Astronomy For Colleges and Scientific Schools. Project Gutenberg, 2011.

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