Koch, H. L. (1966). Twins and twin relations. University of Chicago Press.
Chicago Style aipamenaKoch, Helen Lois. Twins and Twin Relations. Chicago: University of Chicago Press, 1966.
MLA aipamenaKoch, Helen Lois. Twins and Twin Relations. University of Chicago Press, 1966.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.