Cita APA (7a ed.)

Koch, H. L. (1966). Twins and twin relations. Univ. of Chicago Press.

Cita Chicago Style (17a ed.)

Koch, Helen L. Twins and Twin Relations. Chicago [u.a.]: Univ. of Chicago Press, 1966.

Cita MLA (9a ed.)

Koch, Helen L. Twins and Twin Relations. Univ. of Chicago Press, 1966.