title: Usefulness of the co-twin control design in investigations as exemplified in a study of effects of ascorbic acid on laboratory test results.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001205:Ascorbic Acid / Q000627:therapeutic use*; D001774:Blood Chemical Analysis; D002986:Clinical Trials as Topic; D003139:Common Cold / Q000188:drug therapy*; D004200:Diseases in Twins; D005260:Female; D006801:Humans; D008875:Middle Aged; D010919:Placebos; D011247:Pregnancy; D014430:Twins, Monozygotic
chemical_list: D010919:Placebos; D001205:Ascorbic Acid