1. The history of twins, as a criterion of the relative powers of nature and nurture;Galton,1875
2. The genesis of twins;Fisher;Genetics,1919
3. Measurements of Twins;Thorndike,1905
4. Who discovered the twin method?;Rende;Behav Genet,1990
5. Über Zwillingsforschung als Hilfsmittel menschlicher Erbkunde;Poll;Zeitschrift für Ethnologie,1914