3Garcia Vicente E, Sandoval Almengor JC, Dlaz Caballero L'A, et al. Inva- sive mechanical ventilation in COPD and asthma. Med Intensiva, 2011, 35:288-298.
4Aldrich MC, Munro HM, Mumma M, et al. Chronic Obstructive Pulmonary Disease and Subsequent Overall and Lung Cancer Mortality in Low-In- come Adults. PLoS One, 2015,10: e0121805.
5Bansal M, Khatri M, Taneja V. Potential role of periodontal infection in respiratory diseases-a review. J Med Life ,2013,6:244-248.