TY - JOUR A1 - Bergstrand, R. A1 - Vedin, A. A1 - Wilhelmsson, C. A1 - Wilhelmsen, L. T1 - Bias due to non-participation and heterogenous sub-groups in population surveys Y1 - 1983 DO - 10.1016/0021-9681(83)90166-2 JF - Journal of Chronic Diseases VL - 36 IS - 10 SP - 725 EP - -728 ER -