title: Letter: HBAg subtypes in Spain.
mesh_terms: D006509:Hepatitis B / Q000382:microbiology; D006511:Hepatitis B Antigens / Q000302:isolation & purification*; D006801:Humans; D008107:Liver Diseases / Q000382:microbiology; D013030:Spain
chemical_list: D006511:Hepatitis B Antigens