APA (7th ed.) Citation

Ley, W. (1950). The conquest of space (4. print.). Viking Press.

Chicago Style (17th ed.) Citation

Ley, Willy. The Conquest of Space. 4. print. New York: Viking Press, 1950.

MLA (9th ed.) Citation

Ley, Willy. The Conquest of Space. 4. print. Viking Press, 1950.