APA

Ley W., . (1969). Events in space. New York: D. McKay Co.

Chicago

Ley Willy, . 1969. Events in space. New York: D. McKay Co.

Harvard

Ley W., . (1969). Events in space. New York: D. McKay Co.

MLA

Ley Willy, . Events in space. New York: D. McKay Co. 1969.