APA (7th ed.) Citation

Koch, H. L. (1967). Twins and twin relations (2. print.). Univ. of Chicago Pr.

Chicago Style (17th ed.) Citation

Koch, Helen L. Twins and Twin Relations. 2. print. Chicago, Ill. [u.a.]: Univ. of Chicago Pr, 1967.

MLA (9th ed.) Citation

Koch, Helen L. Twins and Twin Relations. 2. print. Univ. of Chicago Pr, 1967.