High incidence of multinodular toxic goiter in the elderly population in a low intake area vs. high incidence of Graves' disease in the young in a high iodine intake area: comparative surveys of thyrotoxicosis epidemiology in East-Jutland Denmark and Iceland. - Laurberg,P.; Pedersen,K.M.; Vestergaard,H.; Sigurdsson,G. (J Intern Med, 1991)