1. Der suizid als genetiches problem (zwillings und familien analyse);Haberlandt;Anthropol. Anz.,1965
2. A twin study of suicide;Juel-Nielsen;Acta Genetica Medicae et Gemellologiae,1970
3. The diagnosis of twin zygosity;Nichols;Acta Genetica Statistica Medica,1966
4. Genetics of suicide: family studies and molecular genetics;Roy,1997
5. Suicide in twins;Roy;Arch. Gen. Psychiat.,1991