title: Norwegian twin registers.
mesh_terms: D000328:Adult; D003327:Coronary Disease / Q000453:epidemiology; D003415:Crime; D004200:Diseases in Twins / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009497:Neurotic Disorders / Q000453:epidemiology; D009664:Norway; D011247:Pregnancy; D011618:Psychotic Disorders / Q000453:epidemiology*; D012042:Registries; D014427:Twins