APA (7th ed.) Citation

Ley, W. (1966). Watchers of the skies: An informal history of astronomy from Babylon to the space age. Viking Press.

Chicago Style (17th ed.) Citation

Ley, Willy. Watchers of the Skies: An Informal History of Astronomy from Babylon to the Space Age. New York: Viking Press, 1966.

MLA (8th ed.) Citation

Ley, Willy. Watchers of the Skies: An Informal History of Astronomy from Babylon to the Space Age. Viking Press, 1966.