title: Letter: Variations in carboxyhaemoglobin levels in smokers.
mesh_terms: D002263:Carboxyhemoglobin / Q000032:analysis*; D002940:Circadian Rhythm; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D012907:Smoking / Q000150:complications
chemical_list: D006454:Hemoglobins; D002263:Carboxyhemoglobin