APA (7th ed.) Citation

Astor, J. J. (1990). A journey in other worlds-a romance of the future. Project Gutenberg.

Chicago Style (17th ed.) Citation

Astor, John Jacob. A Journey in Other Worlds-a Romance of the Future. Champaign, Ill: Project Gutenberg, 1990.

MLA (9th ed.) Citation

Astor, John Jacob. A Journey in Other Worlds-a Romance of the Future. Project Gutenberg, 1990.