Letter: Beta-2-receptor agonists in treatment of asthma.
D000318:Adrenergic beta-Agonists / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy*; D006801:Humans; D009921:Metaproterenol / Q000627:therapeutic use*
D000318:Adrenergic beta-Agonists; D009921:Metaproterenol