APA (7th ed.) Citation

Abell, G. O. (1969). Exploration of the universe (2d ed.). Holt, Rinehart and Winston.

Chicago Style (17th ed.) Citation

Abell, George O. Exploration of the Universe. 2d ed. New York: Holt, Rinehart and Winston, 1969.

MLA (9th ed.) Citation

Abell, George O. Exploration of the Universe. 2d ed. Holt, Rinehart and Winston, 1969.