1. Measures of twin concordance;Allen;Acta Genet. Basel,1967
2. Genetic factors in cerebrovascular accidents;Alter;Trans. Amer. Neurol. Assoc.,1967
3. Environment disorders of the circulatory system;Biörck;Bull. N.Y. Acad. Med.,1959
4. Urban factor and prevalence of respiratory symptoms and “angina pectoris”: A study on 9,168 twin-pairs with the aid of mailed questionnaires;Cederlöf;Arch. Environ. Health,1966
5. The Twin Method in Epidemiological Studies on Chronic Disease;Cederlöf,1966