APA

Struve O., Zebergs V., . (1962). Astronomy of the 20th century. New York: Macmillan.

Chicago

Struve Otto, Zebergs Velta, . 1962. Astronomy of the 20th century. New York: Macmillan.

Harvard

Struve O., Zebergs V., . (1962). Astronomy of the 20th century. New York: Macmillan.

MLA

Struve Otto, Zebergs Velta, . Astronomy of the 20th century. New York: Macmillan. 1962.