APA (7th ed.) Citation

Koch, H. L. (1966). Twins and twin relations / by Helen L. Koch. University of Chicago Press.

Chicago Style (17th ed.) Citation

Koch, Helen L. Twins and Twin Relations / by Helen L. Koch. Chicago ; London: University of Chicago Press, 1966.

MLA (9th ed.) Citation

Koch, Helen L. Twins and Twin Relations / by Helen L. Koch. University of Chicago Press, 1966.

Warning: These citations may not always be 100% accurate.