https://www.nlm.nih.gov/medlineplus/ency/article/000990.htm http://www.nlm.nih.gov/medlineplus/ency/article/000990.htm Asthma Asthma https://www.nlm.nih.gov/medlineplus/ency/article/000990.htm National Institutes of Health (Asthma) ASTHMA https://www.nlm.nih.gov/medlineplus/ency/article/000990.htm