title: Twinning and blood groups. I. ABO frequencies in twins and controls: immunological considerations.
mesh_terms: D000017:ABO Blood-Group System; D001789:Blood Group Antigens; D001787:Blood Group Incompatibility; D005260:Female; D006801:Humans; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D014427:Twins
chemical_list: D000017:ABO Blood-Group System; D001789:Blood Group Antigens