[ABO blood group distribution in ulcer].
D000017:ABO Blood-Group System; D001789:Blood Group Antigens; D006801:Humans; D010437:Peptic Ulcer / Q000097:blood*; D014456:Ulcer
D000017:ABO Blood-Group System; D001789:Blood Group Antigens
BLOOD GROUPS; PEPTIC ULCER/blood