1. Urban-Rural County and State Differences in Chronic Obstructive Pulmonary Disease — United States, 2015
2. Centers for Disease Control and Prevention. Asthma: Most Recent Asthma Data [updated May, 2018. Available from: https://www.cdc.gov/asthma/most_recent_data.htm.
3. Preface
4. Global Initiative for Asthma (GINA). Global Strategy for Asthma Management and Prevention 2017. Available from: http://ginasthma.org/2017-gina-report-global-strategy-for-asthma-management-and-prevention/.
5. Global Initiative for Chronic Obstructive Lung Disease (GOLD). Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease 2017. Available from: http://goldcopd.org/gold-2017-global-strategy-diagnosis-management-prevention-copd/.