APA (7th ed.) Citation

Struve, O., Lynds, B., & Pillans, H. (1961). Elementary astronomy (2nd printing.). Oxford University Press.

Chicago Style (17th ed.) Citation

Struve, Otto, Beverly Lynds, and Helen Pillans. Elementary Astronomy. 2nd printing. New York: Oxford University Press, 1961.

MLA (9th ed.) Citation

Struve, Otto, et al. Elementary Astronomy. 2nd printing. Oxford University Press, 1961.